We pulled my DS6 out of kindergarten in April of last year--we didn't even finish the school year which had less than 2 months remaining. We are homeschooling now for "1st" (but he's accelerated all around) and plan to for the foreseeable future, so I don't have any experience with transitioning back into school. But I will say that my son is so much happier. Although, he was experiencing a lot of anxiety, and that was one of his main challenges at school (along with boredom), so that might be different than your son's struggle.
My son does have sensory integration issues and has been in occupational therapy for many years. We did send him to school with his pressure vest and tried to communicate with the teachers--some were better than others. Gym and recess were hard for him. But we do a number of classes at the YMCA now and he is really enjoying them.
Best of luck!
