You can offer superworms of an appropriate size at any age. I offer baby supers to baby chameleons, and as the cham grows so does the size of super offered. Calcium dust and gutload. They are fatty, so keep to 20% or less of the diet.
I've handled thousands of supers, never been bit. Neither have any of my chameleons.
Have read some people say their have, but doesnt ever sound serious. No worse that a cricket bite.
Supers will crawl up screen, along branches and vines (to some degree); or can be cup fed.