I'll go first.
Don't worry too much about the 90 degree basking spot. He is hanging out where he is most comfortable. Just make sure he is able to sit upright under the heat comfortably. If you see him hanging upside down all the time under the light, then your enclosure is too cold.
It...
it is important to give your new chameleon their privacy, escpecially in the first week or so. let them adjust and get comfortable and avoid handling them.