Cook a frozen cobbler in a microwave instead of oven
It would almost certainly be safe, as there is nothing in a cobbler that could not be eaten if you just thawed the cobbler and ate it raw.

It is unlikely to be as good as when cooked properly in an oven because:


The topping will not crisp up
The microwave will not cook evenly, and you cannot stir a cobbler; you will most likely end up with cooler spots where any thickeners in the filling didn't gel, and still taste a little starchy, and other spots where the fruit is overcooked


It is not really possible to give you a time to use because, even if there was some sort of "oven to microwave" conversion factor (which there is not):


Microwaves vary in power output
The size of the cobbler in question will make a big difference


If you can take it home frozen, I would cook and eat it at home once you have access to a normal oven.