I actually just had a discussion with a friend this morning. If there is any way you can afford to have your son go to Montessori (not just for kindergarten but the long haul) then this would probably be the best option for a child as advanced as your son. With the new play based kindergarten program I have children who were in my daycare last year and this year, that are bored with jk and sk and don't want to go to school....and they are not as advanced as your son. All the best.