Good luck soccermom. I really wish you well.
IMHO, one of the biggest problems that you're going to face is your son's age. IF you move to the Boston area, over time the age issue will lessen. BUT until your son is older, you're bound to face hurdles and obstacles and doors shut.
I was not successful finding a school in the Boston area for my pg son. That's one of the reasons why we decided (rather painfully) to move. My son attended two private g/t schools but neither one worked out; he had exhausted the options with public school pretty early on. I really wish that there was a DYS or equivalent on the East Coast, or ideally in New England, but there isn't unfortunately.
G/t schools in the Boston area are not designed for pg kids. They're designed for mg kids or those working 1-2 grades ahead, possibly 3 grades ahead, but not 4+ grades ahead -- and not for more globally gifted kids. For pg kids who rapidly accelerate, un/homeschooling is often 'it' by default. It's a different story, if you've got a child who is a chess, music, or art prodigy. Ditto if you've got a child who's spectacular in say math but more grade typical in other subjects.
As mentioned, other parents of pg kids have found different stories. I spoke with a parent of a pg kid in Lexington public school system. The pg child wanted to be with his friends and thus tolerated being at Lexington. BUT Lexington, as previously mentioned, isn't for everybody's cup of tea and there isn't much offered until middle/high school in terms of AP or equivalent.
I've heard of pg parents having kids at the British School in Dedham (expensive). I'm sure that there are probably other pg kids scattered around at other private schools too.
I know a pg kid who got a free, full ride scholarship at one of the boarding schools, most likely Phillips Academy at Andover; they take pg kids at 12 yrs old IF 1) they've completed their hs degree from something like Stanford Online HS (expensive) and 2) are socially/emotionally ready. Some parents decide to move to Andover or nearby so they can be day students there. Gorgeous campus!
Other pg parents seek alternative schooling like at Sudbury Valley. That's west of Boston in Framingham and wasn't an option for us.
I know pg parents like us who ended up un/homeschooling. Some older pg kids take courses at Harvard Ext or through dual enrollment (which doesn't start until 14 yrs old). Some enroll the pg kids in homeschool co-ops; Voyagers is a popular one - they're west of Boston in Acton. Others find things piecemeal. MIT has some programming but they're sticklers with age and most of the programs are aimed at older kids. There are some summer g/t programs around here and there, but again these can be pricey.
BU Academy (another expensive school) allows kids to take math courses at BU if they've tested and maxed out of math courses at the academy. Otherwise, you've got to be 16+ years old at BU Academy before you take courses at BU.
