Hot - not hot breaker w voltage tester
Couple things come to mind.


That is a Fluke pen, they are pretty sensitive. I would measure the voltage by sticking it into the slot on terminal screw, not the top of the breaker itself
The front cover on that (what appears to be a sub panel) panel is entirely irrelevant for whether or not the circuits are hot. If you want to make sure it is off, you need to go to the main panel and disconnect it there since there doesn't seem to be a main disconnect (or input breaker) for that panel in the picture