How frustrating! Are these MAP scores from NWEA assessments? First of all, from what my DS's (3rd grade) and DD's (1st grade) teachers have explained to us about NWEAs, when they are in the 99th percentile, it is harder to get points and the assessment isn't as accurate for your student. However, in our experience, the teacher has noticed what was covered in the test that wasn't known, then covered that information. We have been blessed to have responsive teachers who make sure our kids meet or exceed their individual yearly growth, not just the score range goals for their grade. I think DD's yearly growth goal is 17 in math and 15 in reading, with scores comparable to your son's. She has already met her math goal and is 3 points away from reading, only halfway through the year.
The behavior issues seem to reflect what the MAP scores say. Your son isn't being sufficiently challenged and growing, so he is keeping himself busy in other ways. If it was me, I would arrange a conference with the teacher and make a joint plan to differentiate instruction. I would be surprised if the behavior problems persisted after he gets engaged in learning, again.
