True, but so far, all we've seen him wield is the kingdom key. That made some people think that Square Enix was too lazy to program in code for new keyblades. Or at least, leave the alternative keys to a very small role at the end of the game.
And in Chain of Memories, Sora never physically wielded anything but the KK. He used cards to take power from other keys, but his physical key was always the KK.
If that was serious, that isn't Kairi. She's called Xion and is a new member or OrgXIII. The 14th in fact. She also wields a keyblade.We don't know much about here. It's speculated she has SOME connection to Kairi though.