Naruto allowed Kuram alot more freedom after 4th great ninja war, letting him go about freel3y so long as enough Chakra was left behind for Naruto to live and a contract for kurama to be summoned if needed. In this time Kurama decided to follow the sage's teachings and bore new life out of his energy. He created you and gave you a human appearance for more freedom. He himself would take a human disquis3 if in the village but would mostly be in his fox form in private

Welcome back home, pup