The give-on-modifiers 'respawn' is causing an error.
Updated Spigot just now after 1.9 - /version is up to date
Used the default config as well

[21:49:46] [Server thread/INFO]: PrivatePrius issued server command: /kill PrivatePrius
[21:49:46] [Server thread/ERROR]: Could not pass event PlayerDeathEvent to ItemJoin v2.6
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.craftbukkit.v1_9_R1.event.CraftEventFactory.callPlayerDeathEvent(CraftEventFactory.java:399) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.EntityPlayer.die(EntityPlayer.java:421) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.craftbukkit.v1_9_R1.entity.CraftLivingEntity.setHealth(CraftLivingEntity.java:99) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at com.earth2me.essentials.commands.Commandkill.updatePlayer(Commandkill.java:41) [EssentialsX-2.0.1.jar:?]
at com.earth2me.essentials.commands.EssentialsLoopCommand.loopOnlinePlayers(EssentialsLoopCommand.java:98) [EssentialsX-2.0.1.jar:?]
at com.earth2me.essentials.commands.Commandkill.run(Commandkill.java:23) [EssentialsX-2.0.1.jar:?]
at com.earth2me.essentials.commands.EssentialsCommand.run(EssentialsCommand.java:151) [EssentialsX-2.0.1.jar:?]
at com.earth2me.essentials.commands.EssentialsCommand.run(EssentialsCommand.java:146) [EssentialsX-2.0.1.jar:?]
at com.earth2me.essentials.Essentials.onCommandEssentials(Essentials.java:456) [EssentialsX-2.0.1.jar:?]
at com.earth2me.essentials.Essentials.onCommand(Essentials.java:366) [EssentialsX-2.0.1.jar:?]
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.craftbukkit.v1_9_R1.CraftServer.dispatchCommand(CraftServer.java:645) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PlayerConnection.handleCommand(PlayerConnection.java:1350) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PlayerConnection.a(PlayerConnection.java:1185) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_73]
at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_73]
at net.minecraft.server.v1_9_R1.SystemUtils.a(SourceFile:45) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.MinecraftServer.D(MinecraftServer.java:721) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.DedicatedServer.D(DedicatedServer.java:400) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.MinecraftServer.C(MinecraftServer.java:660) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.MinecraftServer.run(MinecraftServer.java:559) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_73]
Caused by: java.lang.NullPointerException
at me.RockinChaos.itemjoin.utils.Listeners.isAllowedItem(Listeners.java:578) ~[?:?]
at me.RockinChaos.itemjoin.utils.Listeners.onDeathDrops(Listeners.java:524) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_73]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_73]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_73]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_73]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot.jar:git-Spigot-23e921f-8b69bdd]
... 29 more
[21:49:46] [Server thread/INFO]: PrivatePrius died
[21:49:48] [Server thread/INFO]: [ChatEx] There is no new version available. You are up-to-date!
[21:49:48] [Server thread/ERROR]: Could not pass event PlayerRespawnEvent to ItemJoin v2.6
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PlayerList.moveToWorld(PlayerList.java:626) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PlayerList.moveToWorld(PlayerList.java:555) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PlayerConnection.a(PlayerConnection.java:1606) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PacketPlayInClientCommand.a(SourceFile:31) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PacketPlayInClientCommand.a(SourceFile:8) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_73]
at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_73]
at net.minecraft.server.v1_9_R1.SystemUtils.a(SourceFile:45) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.MinecraftServer.D(MinecraftServer.java:721) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.DedicatedServer.D(DedicatedServer.java:400) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.MinecraftServer.C(MinecraftServer.java:660) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at net.minecraft.server.v1_9_R1.MinecraftServer.run(MinecraftServer.java:559) [spigot.jar:git-Spigot-23e921f-8b69bdd]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_73]
Caused by: java.lang.NullPointerException
at me.RockinChaos.itemjoin.utils.Listeners.onRespawn(Listeners.java:65) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_73]

Nice trick lol. I will look into this soon. Its going to take some testing since I see some essential bugs in there so I will have to figure out whats going on there. I will get back to you ASAP!

Also next time use pastebin.com to post error codes in and link it to me.

Not sure how you obtained this error but it seems to be fixed in ItemJoin v2.7. I have done extensive testing on this and there should be absolutely no errors.

I plan to release ItemJoin v2.7 tomorrow so look out for it!

Thank you!
I plan on opening my server tomorrow and am looking forward to this greatly! Thank you for the fast response as well!

How soon are you expecting to release v2.7? I'm very anxious

It has been uploaded and waiting for appoval. I am forwarding you that it may be a bit confusing and first to setup. I have completely redone the items.yml structure. Instead of the slot defining the item now a random name can define the item and the slot is defined under that item.

Awesome! Any way I could get a dropbox/drive/mediafire link? :) :) :) :)

http://www.spigotmc.org/resources/itemjoin.12661/ uploaded here and already available