Is that your cham in your avatar? Cuz he looks much older than 8-9 months! I'd say at least a year, if not older. I've had my boy Jax (in my avatar) since he was a baby, and is currently about 8.5 months old. As you can see, he looks nowhere near as developed as your boy. Did you get the jackson from a store? Cuz most of them have no idea what they're talking about. I've had someone tell me a Jackson was 4 months old, when it was more like a year and a half.
Question, when your Jackson is "running laps", is this in his plants or on the cage floor? One of my Jacksons likes to lap up water from the floor whenever I'm misting and if the drip system is running. He'll just walk in circles on the bottom drinking water for 15 minutes or so. That's the closest thing I can think of in my experience with Jacksons "running laps". If that's not the case, I have no idea. Either way, a moving cham is a healthy cham