D.T.
This is a very common issue for boys. I would recommend holding him out of kinder for a year and keeping him in pre-k. Check with local churches and even the school district about different pre-k programs. Lots of kids are 6 when they start kinder- he won't be unusual. It is a better choice than having problems all year and possibly having the school hold him back. My neighbor went thru this and he is in kinder now and doing great. Extra pre-k was definitely the right choice for him.