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.
This sounds very close to what my husband did back in the 1970's, although in his case there was no AoPS or Egpi so he was just tutored by a college student. For all other subjects he stayed in regular schools. And he started taking classes at the 'local' university by the time he was 14 although in his case the 'local' university was one of the elites. He graduated from university in 3 years since he had so many university level courses. Went to an excellent graduate school & is now one of the top in his math related field. (Even this vague answer seems like I'm revealing too much on a this public form.) Looking back this worked out very well for him.
