We're homeschooling. DS8 is extremely mathy, working through AoPS Intro Alg book at the moment. But he may only be MG in other areas such as verbal/reading, and is not socially skilled.
So here are my thoughts. We don't anticipate early college (maybe 17, but not 15 or less), due to social skills and not being highly advanced across the board. Also we want him to get into an elite undergraduate college, which is much more realistic at regular college age than younger. He could conceivably start earlier at the local state uni, and then go for an elite uni as a graduate student, but I strongly feel he should get with the strongest possible peer group as an undergraduate. (I personally regret going to the local non-elite uni as an undergraduate, even though I did well as a graduate student at an elite uni.)
So how does DS8 avoid early college when he is 5 years accelerated in math? Firstly he's not much accelerated in other subjects, and probably won't be, so early college is not really an option anyway. Secondly, when he finishes high school math he can just continue with college math, while still officially being a K-12 student. He'll probably do AoPS calculus (and take AP BC exam) at age 12-13, and then if possible start taking math courses at the local (decent not great) state uni, and at the end of high school will have covered the full undergraduate math curriculum. If he can then get into an elite uni then that's great, even if he has to retake more rigorous versions of courses he's done. If he doesn't get into an elite uni, then maybe he can complete a BSc at the local uni in about 2 years and then try for an elite uni as a graduate student.
The quality of the local uni is important. Ideally you at least want many faculty who came from elite unis. And you can check the entrance scores of the student body. If there are honors courses that helps. There is one decent uni near us and another uni and a community college near us that are complete rubbish.
