The fun thing is, we already heard of this "endorsement needed for getting to the Academy" all the way back in TOS "The Apple". There, it was said that James T. Kirk had gotten it himself, from the father of Ensign Mallory.
Should we perhaps deduce that Kirk wasn't a Federation citizen back then? Despite him supposedly being born on Earth, in Iowa, this could well be possible - his childhood involved an episode on Tarsus IV, an isolated and seemingly isolationist colony where little Jim's parents are conspicuously absent. All sorts of backstories could be spun from that.
Of course, Jim could have been endorsed even if he didn't need to. But Kirk seems to think the role of Daddy Mallory was important in Kirk getting to the Academy.