Jinchuuiki, Tailed beast there are nine of each. They only met during the war right. But I want to tell you what would happen if at the time when Mizuki told Naruto about the nine tails. Naruto and Kurama had an understanding because Naruto met him when he was two and because of this Naruto formed the Jinchuuiki alliance.

P.S. I don't own Naruto but boy if I did mahahahahahhahahahaha