My son had an AmeriCorps volunteer in Kindergarten. She sat with him and guided him on computer based learning for half the day, in his classroom. It was a nice arrangement where he didn't have to sit through the lessons he already knew, but he didn't have to leave the classroom. One of the more unusual arrangements that you can keep in th eback of your mind. It happened to fit the school's resources at the time.

I am not buying the "small for age" argument! I have been pressured with it since my son was 4. He is 11 now. He was miserable in elementary school when accelerations were not taken over "he's small for age" and puberty worries. He did poorly socially - so poorly I used a home-based education until 5th grade/this year. He was skipped into 6th (homeroom, gym, etc) 7th (science) and 8th (math). He holds his own in gym class, even though he is not athletically inclined. He has more friends than I can keep track of now. He's still small for age and the second smallest kid in the school. (The smallest is an age-mate, girl, who was grade skipped past Kindergarten at the same time/in the same school that was ao insistent my son was too physically small). Gender discrimination much?

Gifted children who are athletic have the best social outcomes. It's a protective factor. Your son is in a very good situation for however you choose to have his academic needs met!