P.K.
There are a few things to rule out before you start beating him and depriving him of any childhood joy.
Sugar is an obvious one. Cut it out for a week. Don't forget that many juices are LOADED with sugar also. He will hate you but he's going to hate you when he's a teenager anyway so consider it a head start. He'll get over it.
Put him to bed earlier. Kids who are tired will act out because they are trying to keep themselves awake and alert.
Cut out TV in the morning. I did that with my son and it's made a huge difference. I have no idea why but it does work for me. I think it's because he gets overstimulated.
Are his meals large making him feel 'napish'? Fill his lunchbox with light foods like fruit and a half sandwich with water to drink.
Does he snore? Much research has been done on children who have tonsil, ear, and or allergy issues that exhibit behaviors associated with ADD and ADHD. The theory is that the child doesn't breathe well at night and has a more difficult reaching REM sleep because their bodies 'wake them' too often. When you toss and turn you don't get a good nights sleep. It's the same with kids. My stepdaughter had horrible issues with sinus infections and ear infections. I urged her mother to consider surgery to remove the tonsils, adenoids and put tubes in her ears. When she was 10 her mother finally decided to have the procedure done. Overnight her behavior improved at school and she was more interactive in class. Her teachers realized she was smart and she could sit still. She had ears so full of gook all the time she didn't ever get a good night's sleep and she didn't hear well. She was tired, deaf, and bored! If you son falls asleep in the car ride home from school he's not getting enough sleep. If he is snoring see an ENT to find a way to remedy the swollen tonsils.
He may be wired up because he does have ADHD or whatever they call it now. If so the teachers should work with you just like they would for any child who had something that made learning harder. I'm dyslexic and have adult ADD. I'm also very smart and creative. My parents and teachers didn't tell me I had these issues until I was out of high school. As a result I didn't feel like a 'bad' kid who was 'stupid' like the other kids I grew up with that were diagnosed with these problems. Hyperactivity isn't a curse. If his body works that fast so does his mind it's just a matter of channeling the energy in a productive way. Most of the people who build huge successful companies on a shoestring budget can pull it off because their minds are in a lot of places at one time and they see opportunities that others miss. I'm a math semi-genius. I can figure out ridiculous equations in a snap but when I have to add the tip on the bill it takes me forever. When I see the numbers they get all goofed in my head and I can't add. Not being able to add was/is embarrassing but being able to do complex things in my head makes people forget that I'm the dummy who can't add.