Regardless of the rule set, for a receiving team player to catch a free kick in the kicking team's end zone would, indeed, be exceptionally freaky. By the laws of physics, certainly not impossible. But, as others have noted, it would take a very an exceptional set of circumstances. In any event, it would surely require the kicking team's restraining line to be their own 10 yard line or so (relocated by penalties).
Nearest to impossible would be if this was a kickoff (punting not allowed). But, I suppose a a really hard kicked ball that traveled straight ahead could deflect off receiving team player's helmet or shoulder pads, and fly up and backward (toward the kicking team's goal line), high in the air enough to allow a really fast receiving team player to run under it and catch it in the kicking team's end zone.
Only very slightly less freaky would be if this was a free kick after a safety, with a punt by the kicking team. A high punt blown by a typical West Texas Friday night wind could do the trick, blowing the ball back to the kicking team's end zone where that same really fast receiving team player could run underneath of it and make the catch.
Not really my field or expertise (NFHS), but the rule language provided earlier indicated "catch or recover," and I think the recover component of that language is far more likely to happen. In either of the two scenarios I offered above, the ball is more likely to return to the ground before anybody - especially a receiving team player - can get to it. So, not much chance of a catch, but a somewhat distinct possibility of a recovery.
