I would love your perspectives.

DS 4
All around, total mastery of Kindergarten academics by 3.5
And I mean completely 100%. He reads, writes, spells, does math at a 1st grade level.
Mostly self-taught with some help.
Loves preschool right now.
I.Q. was 138 on the WJIII-Cog. Underestimate. Two psychs said mid 140's would be a more accurate scoring. (you know why I say this because 138-144, depending on the test is different than 145-152, so we don't really know yet if he's HG or EG, which could matter if we talking prediction of how well any school can accomodate him).
We are in CA. He is not supposed to begin K until 5.5
My husband and I have gone around and around this for...years of course. But as it gets closer, he is clearly 2 solid years ahead of his peers.
He does not like to be bored. He does not like to go over concepts he already knows. He thinks all kids are like him. He is extremely social, verbal and loves all kinds of people. He says he wants a playdate every single day.
He dominates play...but is learning. Kids do like him at school and he has developed many friendships. Their parents have said their kids talk about him at home, which is reassuring that the friendships are not one-sided.
However.....he is highly explosive at times. It's improving but still part of the way he expresses extreme emotion. We are working on a new system a child pychiatrist for identifying emotions and it's working, but worrisome and has been like this since he was one.
He doesn't hit children at school, he doesn't hit his brother, age 2 very much, and when he does, it's very light. I'm his primary target (I'm a SAHP).
His teachers keep saying, "Don't put him K early, give him another year to play with cars and trucks."
UM. Cars and trucks? When did my son play with typical toys? Have you not met him?
I feel so misunderstood by them and when I engage in conversation, it's the same response from them. They aren't saying he's not ready or that he does poorly in this or that, it's an issue of forcing him to be in school early means a year of his childhood is taken away.
Ok, so they are obviously experts in NT preschool kids and I trust them to an extent. And as it turns out, one of them has G children herself.
I feel like they don't know him in the same way I do. So I question, would they see it differently if they saw the work he does at home?They do very little academics and when he brings work/art home, I can tell that he was doing what he thought the teacher wanted to see but not what he actually can and does do at home. I think they believe that all of the other parts of K are fulfilling enough and that he won't notice he's doing work that he did when he was 2.
My husband and I both look ahead and see a depressed child. He scored high in anxiety and depression on some evaluations. I can't imagine him being OK with doing work he literally did 3 years earlier.
So, I'm pushing on and trying to get a process going. The principal of the school thinks its a good idea for him to attend early or maybe just go into 1st grade early, his pychiatrist thinks it's a good idea to go early. But are they appeasing me by saying this?
What am I missing in his teachers' points?
I don't want to make a huge mistake either way. I feel like there should be a clearcut evaluation process for early K, a checklist, but there isn't.
I don't want him to be the youngest kid in the class, I don't want him to be last to get a driver's license among his peers, of course I don't want him to experience disadvantages from being the youngest. BUT, come on, he is who he is. Will he be in college early? Probably, so does any of the early age disadvantages matter? Probably not.
I do not want him to begin K and then skip to 1st, a full year of 1st is important.....or is it?
I read a post one of you lovely people wrote last night that K will be trial and error no matter what and that's helping me get through this.
Thank you for your input.