How do you begin to handle a situation like this? son setting counter on fire?

My son is 8 years old and at times can be destructive.. our main problem is he likes to get on the counter and turn the burner on the stove. He knows better but yesterday he did while I was in the other room and set a paper towel on fire which spread to a plastic spoon and spatula. It almost burnt the counter uo by the stove. My husband and I flipped. I set up an appointment with a therapist to see why he is so destructive. At the same time problem or not I do not believe he should of gone unpunished. His dad gave him a big and he has lost every privelag he has pretty much. What could be wrong with him and how would you handle it. Should he hsve been ed. Should we go to the therapist. Please help