I really don't see his behavior becoming problematic. Of course, "problematic" is subjective to the teacher's POV. He's just not one to be intentionally or maliciously disrespectful to his teachers.
I think your idea to leave it alone, is essentially what I've been doing and will, most likely, continue to do. Knowing that he won't be in a traditional school setting next year has changed our attitude a bit - again, just trying to hang on and make sure that he's doing OK and not getting into trouble. If he's redirected by the teacher from time to time, that's not a big deal or what I would consider "trouble".
I've also speculated (with DH) that some of this may be a difference in maturity for DS, and that can only be solved with time. She may be keenly aware of some of these...traits? in DS because he is 1-2 years younger than her other students, and therefore, they're quite noticeable. And well, part of it is just because he's made that way,

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I've enjoyed the discussion and it's nice to know that there are other folks out there with such wisdom and experience. Thanks! Might I ask...how is your son doing now? Is he still in school?