Hmmm... well a perfectionist may be cautious on the test... afraid to give a wrong answer...

Could that have something to do with it?

If he asks about the test, I think I would just tell him that he did a great job, and that you know he has a lot of talent and potential. No need to talk about the actual number... if he wants more concrete info, you could say that the results showed that he is well-rounded and shouldn't have any problems in school.

It's a shame that your school restricts the math competition and science fair to gt identified students. That seems close-minded. Personally, I think that activities like that should be open to all who are interested.