Is it possible to reenlist with a Chapter 9, RE-4, Honorable?

Your best bet would be try to talk to an active Recruiter, as they'll have the most up to date idea. But good luck finding one who's going to give you the time of day with that Discharge type. I'm not even sure if that sort of RE-4 is waiver-able, since you already failed your chance to get over your substance abuse problem on the Army's dime.

I'm pretty sure a RE-4 code is NON-waiverable no matter the circumstances.

RE4 is not waiverable.