Hello
After loading my save I noticed that I lost my inventory. My kerbal was saved out of the ship and had already start working with his tools. I think the only item left was the wrench and was equipped.
I was able to move and build parts without wrench, but after a reload, still no wrench and I wasn't able to build anymore. This is more than odd.

Game v 1.10.0.2917
KIS 1.25

I remember having a crash yesterday. I just installed the 1.26, my item are still lost.

This isn't the first time that I lose an item. The first one was after I pressed enter to cancel an action. There is a global thing to fix to improve the reliability of the inventory system, even in case of crash...

Is there anyway for me to edit the save and get my wrench back ?

I need logs to investigate this issue. A definitive list of steps to reproduce the issue would be the most helpful. KIS is a reliable mod that worked well for years. There can be edge cases introduced by the third party mods, though. At this point there are no known stability issues with KIS 1.26 and KSP 1.10. There were issues with 1.25 though.

I just installed the 1.26, my item are still lost.

If the items are really lost (like, removed from the save file), the only way to get them back is to reload an old file - before the problem happen. If you simply re-loaded the current game after first time observing the issue, then the items are already deleted from the game state.