DS2.8 will be going through developmental screening next Thursday with the main concern being Autism mainly for speech delay, tantrums, sleep problems, refusal to follow directions, etc. but a lot of it may be masked giftedness (knew all upper and lower case letters and sounds before 24 months, started reading words phonetically at 2 years 4 months, counted objects to 20 by 24months, started with basic addition little after 2.5 years, etc.).
I think you might be misunderstanding giftedness. Poor behavior, not listening to directions, tantruming, etc is not a symptom of being gifted. Now, it might be that he's not be directed in a way that helps him deal with frustration, but those are not signs of being gifted.
I hope the screening helps you figure out where the problem lies and how you can help your son interact more effectively.
