Try contacting school boards and private game/computer science education institutions! Like other people have been saying, your market is definitely between educators, kids, and parents of kids around those ages.
I still remember lots of the "educational" games I played as a kid (Math Circus, Math Blaster, Cross Country Canada, Magic School Bus: Dinosaurs, etc...) very fondly, and have made an effort to collect and replay them whenever possible. What I have noticed playing them as an adult is that the educational games I remember most are those that refused to sacrifice the depth and quality of the game mechanics for the sake of teaching the player something. If I could suggest anything while undertaking a game like this, it would be to make sure players are learning through playing, and not playing to learn.
...if that makes any sense