The approach that we use for our DS9 is a combination of both. At home we mainly let him pursue things that school doesn't cover. At school we try let the teachers understand that DS9 needs acceleration. So far, DS is not challenged enough at school but he does sometimes get more advanced stuff than other kids. Given that our entire school is pretty advanced (I heard that the average kids at my son's school are about 2 grade levels above state standards), we are fine with what DS gets at school. He still has lots of free time at school but as long as he likes school I'm fine with it.
School education, in my mind, can be quite narrow and shallow, though. Topics are taught superficially, and lots of important areas are not covered. And that's what we make up for at home. We revisit the same math topics that are covered in classroom but much more in-depth. We read much more advanced books together. Museums, musical instruments, and yes, paper airplanes are DS's longlasting hobby. Basically I think if you pursue acceleration only, lots of learning will not have the depth that they should have. If you don't pursue acceleration at all, well, kids might waste too much time at school.
