Well, remember when sora and kairi are looking up at the sky with a meteor shower and sora falling along with the meteor shower? And if unlocked the secret teaser at the end there is a girl on Destiny Islands looking at a meteor shower? Well I think that whenever the sun is setting on Destiny Islands and you look into the sunset you can see you're destiny as the name destiny Islands inplies. And at t he end of the infamous not so secret Kingdom Hearts 2 teaser there is a girl on destiny islands looking at a meteor shower and it's the future, which means when Sora and Kairi looked at the sunset it they were looking into the future which the name Destiny Islands means. Clearest way I could explain it.