8 year old son touched at school

Hi my son is in 3rd grade and I was so shocked today when his teacher pulled me aside at pick up and said my son told her that this boy in his class had been touching him in his private area since September (around 30 times). My son says anytime this child was annoyed at my son for doing or saying something he didn’t like, he would grab him or hit him in the private area. I’m so surprised at hearing about this so late but also how do we go about this situation? The teacher said she was going to speak with the parents and file a report but I feel that they need to be separated. What would you do? Are they still too little or old enough to know better? Am I overreacting?

UPDATE: thank you everyone for the advice. We are in Canada so things might work a little differently here. I’ve requested a meeting with the teacher and the principal tomorrow to see how they can separate this child from my son. It’s my impression they weren’t planning on contacting me first so I don’t think anything was going to be done on their end proactively. THNK YOU FOR ALL THE COMMENTS