I'd like to encourage you to rethink the words "discipline" and "bad".
First, discipline means to teach. Punishment is handing out consequences. For example, we discipline our toddler when we tell her "when we're in the parking lot, heading to the playground, you will hold Mommy's hand. That's to keep you safe.". Then punishment is doled out when the toddler shrieks, lets go of your hand, and tries to run in the parking lot to get to the swings. The punishment is: you get right back in the car and go home. No playground today. We'll try again tomorrow.
So in fact, you can be disciplining your son about behavior. You can help him understand that he is a ball of energy, and active, and that's a great thing. You can acknowledge (without going overboard) that you appreciate his cooperative behavior during guitar lesson time, and how that behavior makes the teacher's life easier and that it shows that he understands how to sit still, and can, in fact, sit still.
You can teach him to be a little more aware of how loud he is; perhaps a subtle hand signal that you practice with him during a calm moment to signal "hey, your voice is kind of getting too loud" would be helpful.
Next, "bad" is not necessarily loud and rough and tumble, unless we're talking about being in line at the grocery store and the kids get rough and the old lady in front of you is knocked to her feet because your kids were out of control. A 9 year old healthy boy can have a ton of energy. You just have to teach him to be considerate of others, and to not just run without looking. You have to teach him that some kids don't want to wrestle, and some kids cannot wrestle, and how to know the difference. And there are times to wrestle and run and tumble, and times not to. "Being bad" means knowing the difference and refusing to acknowledge that now is not the time to wrestle but to listen, and that the kid who was sitting and reading a book quietly did not deserve to be jumped on like he was on the football field. If you help him appreciate the times when you loved his energy ("great footwork in soccer today!"), and times when you appreciate his appropriate behavior ("I liked how you paid attention immediately when Mr. Cub Scout Leader asked for everyone's quiet mouths and quiet feet. Good job!"), you'll help discipline him to be an energetic, all-boy, but polite and appropriate kid.
Can you give him some physically active chores, like raking leaves or shoveling snow? Could he do it for a neighbor, maybe a young mom with babies or an elderly person? Is there another chore that requires time and energy that you could assign to him?