That's a tough question and probably subject to opinion. I'd say that there is an innate range that a child may fall within. Where he'll settle in that range probably won't be known for some time as IQ scores are somewhat unstable at his age. In general, though, I'd say that you can raise your IQ score by working on the types of skills tested on IQ tests, but that won't truly change your ability.
One question, do you have a history of giftedness in your family? If you are comparing him to others with high IQs in the family (125+) and he still seems very bright (on par or above them), you might have good reason to think that the numbers are not the best estimate of his ability.
