[Yes, yes he is a jerk. But at least he's not trying to kill Goku anymore.]

You were reduced back into your child self, but that old bumbling idiot of a Kai regrew your tail for you. So yes, your future self will be able to. But that requires transforming into the Golden Great Ape, and if you recall you don't exactly have the training to be self-aware when you take that form. And your granddaughter isn't here to help you remember. [And he doesn't want to deal with a Golden Great Ape Kakarot. That's just going to spell out problems.]