That seems like a heck of a lot of heat for one tank. Don't measure anywhere but right on top of the substrate. Hot side should be between 82-85 and cool side should be between 75-78. You want to measure surface temps, not air temps. Make sure to use a good thermometer, not one of those stick on ones.
You can leave him alone for about a week before beginning to handle him to get him acclimated to his new home.