I do not know where to begin to consider an IQ test.
Who administers an IQ test?
What is the best test for his age and ability called?
Is an IQ test intrusive?
Will it make my child or me feel uncomfortable?
Is it worth the time and money involved?
Why would I do it?

He has taken the CAT test for three years. I always test him one grade level ahead and he scores between 90-99 percentile in each subject.

I feel in the dark. I know I have been meeting his needs up until this point (since he started reading at age 3), but now he is getting a little bit difficult to life with (inundating me with endless questions and wanting complete control of his surroundings.) That is why I had him tested. He is adopted, so he doesn't get it from me. So, I am having difficultly understanding his personality.
Thanks for your thoughts.