So good of you to adopt this cat...

I take it you gave him a box with a towel in it and put it in your closet with the door slightly ajar, so he feels safe, eh? If not, I'd suggest doing that. Place food and water a couple of feet away outside the closet and a litter box further away still...

Maybe keep the door to your room closed for now so Jimi gets used to that space and feels safe, then you can eventually open the door and see whether he comes out on his own.

I'd go into the room to read, play soft music, talk quietly a bit, sleep but essentially do this while ignoring him and letting him make the first move.

There are YouTube videos search "how to tame a feral cat youtube" or "how to socialize a cat"

You are a good soul for adopting Jimi... let us know how it goes...