DS7 has also been chafing at the super-simple science lessons that have only really begun this year (third). I've responded to that by getting him science stuff to work on at home. I guess in that instance I'm afterschooling, but there's no other option but to let the school slowly dull his interests.
I think science is different, because it's so incredibly broad...you could afterschool/enrich in science in a million ways and run little risk of overlap (I would choose slightly obscure things...as in, not germination or the 3 kinds of rock). We are a very sciencey family, so we essentially afterschool in science constantly, though it isn't bookwork. This helps a lot.
I don't want to sound like I'm defending the school, but it is hard for them when a child can easily go so far ahead. Would they let him work solo on something like Khan? I would think that might be your only option.
