Hi, my 9 year old boy behaves rashly sometimes! I was told that they get a testosterone boost at around this age which sometimes leads to challenging behaviour. Also his appetite has gone through the roof (which might be why your son couldn't resist the chips!) so i am assuming a growing spurt too. We have the three tier system so he is in Year 4 which makes him in the top year at his school. This tends to lead to "big fish little pond", I am sure he will settle when he gets to the new school in Sept.
Your son is innocent. He had no way of knowing. So there is nothing you need to do. Also, I don't know that these French fries were worst for him than what you ordered. MacDonald is not a good place to eat. It is junk food and is bad for health, behavior, and intelligence development. Stick to real foods and real foods restaurants and there won't be trays laying around with food.
