D.H.
I think he is scared also.......try getting there early, and maybe having the teacher greet you......get him in his seat. Also, start talking to him on the way to school about what he might do today, learn, see....etc.....then on the way home, go over what he learned and did........make it more grownup for him.....that way you two have a bond that you don't have yet with your 2 younger daughters...tell him soon he will be able to help them adjust to school just as he is.....and what a great big brother he will be.....
If that doesn't work, then you are going to have to decide if you should ground him for his behavior, or take away things.......that the other kids do not act this way and he needs to be more grown up. Definitely ground him for pulling your hair and kicking.....
Another thing you might do to help him, is play school games with him at home......ask the teacher what they are going to be doing for the week and then work with him at home so he feels more comfortable.....
Let him know that you miss him while he is at school, but how very proud you are of him as well.......
Take care and good luck.