You are strong enough once you reach Orphan that going back to Pulse and killing some of things is possible. All of those Behemoths and small Adamantoises are actually possible for you to kill now. You can probably Death the larger ones if you really want to do it. So it is up to you if you want go back. You're strong enough to deal with the rest of the main game if you so wish to do.

I pushed on to the end of the game and did not leave until I was at the very end of the game.