Can I fill a drywall hole with something and reuse the hole?
You haven't said how big the hole is or what it's for, but I think I understand your question, how a little filler might not be as strong as untouched drywall. It depends on what it's filled with, but regular drywall filler probably won't be as strong. If you're just hanging a small picture I'm sure filler would be perfect.

If you're hanging something very heavy and you want to make sure it's a strong patch, and if you don't mind a hole at least an inch or two and a little patching &amp; filler &amp; paint you could put a piece of wood behind it and screw it into the "good" drywall on either side:



Then patch it with the larger drywall piece you cut out (if you cut it out  carefully). 

Now your "new" drilled hole will be just as strong as the wood behind it is held, probably 4x a single screw in drywall.