As you might see lots of people said that you can not judge a kid is clever or not from his score in primary school. I was almost the last rank in primary school. In high school I got lots of nation-wide academic awards. From yr story I think yr son is a very good kid and has great thought than other normal kid at the same age. Money is a matter but NOT always.
People can change.
I used to get 60th place with 60 students in the room when I was in 7th grade. Now I'm in the first place in the class. I used to be very bad in everyway. I was bad in sport, music, art, and study. People can change.