"I think he is getting his needs met, but mostly at home."

Aha, after you really think about it, sounds like his needs are not being met at school. To a gifted child, those intellectual needs are just as important as those social needs.

You are talking to us, not the teacher, so don't worry about protecting teacher's feelings.

Time to get real as old Dr. Phil likes to say smile

Sounds like you are on to a good plan. Testing, investigating options for school. It can be a daunting and fun process!
Good luck and this forum is a great sounding board. Hope it helps you.

Incog