His behavior is normal. The problem is our new test driven educational philosophy isn't taking into account actual child development.
ADHD is grossly over diagnosed, as are so many of the "other" conditions, like sensory processing, etc. a lot of it is pure social construct B.S. we are labeling kids with "problems" that years ago would have been seen as normal, I.e. oh, the kid is a bit immature, he will grow out of it by 8.
Part of the problem is we are asking 6 year olds to do in school what 8 year olds use to do without regard for emotional and physical development.
I homeschool, and I have met so many families that had to pull their boys from school because they couldn't sit still. Of course not! The kid is 5 or 6, and should be outdoors playing for the bulk of the day, not writing and doing boring worksheets!
Also, we get our teachers from the bottom of the educational pool. Most of them aren't very literate or smart, or even good with kids. Some are terrific, but a lot of them are terrible. I use to teach the brightest educational majors in Illinois. Most weren't very bright. I hate to say it.
My point, give him lots of unconditional love and support, and I am sure everything will turn out fine. If you start down the testing path, you immediately put your unconditional love for him into question, and this can only create more turmoil.