Hmmmmm.... sure, he may try a few things that the other kids wouldn't, but he should still be listening to and respecting you. I would not expect anything different from him, simply because he knows you better than the other d/c kids.
It sounds like a) he likes the attention it brings him, even if it's negative and b) the yelling no longer impacts him.
I agree with playfelt; when he hits, you need to get down to his level, grab his hand firmly (not roughly) and just say "NO. WE DO NOT HIT." I would not give him any big reactions, except to immediately take him to a 3 min time out. Hopefully consistency in taking him out of the situation without fuss or fail will work for you.
Good luck!!