I am going to create a thread to answer this once and for all
Kairi had the keyblade because it was given voluntarily to her by Riku
No keyblade wielder needed it for anything
it is my theory that if the wielder wants whoever has it to use it or is unconcious
the keyblade would be able to be wielded by whomever it is given to
In Kairi's case Riku gave her the Blade and willed it to stay as if commanding a dog
Leon wielded it in KH1while Sora was unconcious
It came back to Sora because he did not will it to stay
Hopefully this will stop all the crap I hear that are literally crackpipe stories
Kairi had the keyblade because it was given voluntarily to her by Riku
No keyblade wielder needed it for anything
it is my theory that if the wielder wants whoever has it to use it or is unconcious
the keyblade would be able to be wielded by whomever it is given to
In Kairi's case Riku gave her the Blade and willed it to stay as if commanding a dog
Leon wielded it in KH1while Sora was unconcious
It came back to Sora because he did not will it to stay
Hopefully this will stop all the crap I hear that are literally crackpipe stories