No, do not use bondo. NG below the waterline.
But a quick easy fix is just to fair it in with epoxy/microglass - and then keep an eye on it. Yes, cutting it out and replacing the core and skin will make it like new. And no, the 'filler' isn't as strong as a proper repair. But doing the epoxy filler doesn't rule out doing the 'like new' at a later date.