Mod doesn't work on Minecraft 8.9 without adding this library to the classpath:

        {
            "name": "it.unimi.dsi:fastutil:8.5.12"
        }

After adding that, I get a dependency error stating I need to install SpongeForge 7.4.8 or greater... on the client. Attempted to do so just to see if it would somehow work and shockingly it did not.

I'm still getting the spongeforge dependency issue on latest 9.1.

I misread Minecraft 8.9 as MixinBooter 8.9, you mean Minecraft 1.8.9 right?. I'll fix this for next release.

Yes, sorry for my phrasing there. Thanks!

I misread Minecraft 8.9 as MixinBooter 8.9, you mean Minecraft 1.8.9 right?. I'll fix this for next release.