Relax.
In one of my parenting books, there was this foreword:
You will spend the first two years teaching your child how to walk and talk and the following 16 how to shut up and sit still. Relax, everything will be fine.
Some teachers do not understand what being a 4 years old boy mean. Does your DS do it on purpose? NO. Does he mean to disturb, no. School just started, he is learning what is expected of him and since he doesn't know what he did wrong, someone did a poor job at explaining the rules to him.
Be polite to the teacher and ask for example of how disruptive he is. It could be the pencil case falling on the floor. I have been an ethics teacher here in Australia, and I have seen teacher's interaction. Sometimes they take a particular "attention" to a child, and whatever that child will do, even a sneeze, it will be outrageous.
Talk to your son explaining that school has some rules that requires children to be very quiet. That you love your son's energy and the fact that he is joyful, but school is a place where you need to control your energy. But that's okay because you know that he will be able to.
Don't be anxious or stressed. Go to the meeting with the idea of coming out with a plan. Ask the teacher what is the main issue for which she tells him off 7 times in a day, and then ask her if she praises him when he tries to make an effort.
And to be honest, I am yet to see a child who will listen 100% and have blind obedience. If there is one, I would be seriously worried for their mental health.
Your son is 4. He just started school. HE needs you to help him make it successful. So, at the next school run, be at the front to pick him up.