I don't know what you mean by "concerned that his behavior isn't necessarily exclusive of the whole gifted/academic thing", but I wouldn't let that psycho near my son! Just the sound of it makes me uneasy.
I think a grade skip would be a good starting solution. Subject accelerations might be another option too. However, you definitely need more info. Feeling that, as you say, "he can probably complete most of the curriculum in Math already" doesn't necessarily translate to maxing out of the curriculum in the building. I think you would need to find out what his achievement levels actually are, mapped to their curriculum, to determine further what's appropriate. In the absence of more info on writing ability I couldn't guess at whether a grade skip to second was appropriate skill-wise.
It sounds like you're going to face resistance to acceleration right now because of the behavior issues. You need to do your best to get your son to tone it down, perhaps explaining to him that you can't help get him more appropriate work while the school sees him as acting inappropriately.
I'd also start reading up on behavioral and emotional issues of gifted children; select materials showing that disruptive behaviors can be a consequence of combined boredom and intensity, and give them to the school or at least bring them to meetings.
Why don't you involve your DYS family consultant? This is their bailiwick.
