Kingdom Hearts II Is there any mention

That Kairi writes that poem?
I mean... maybe her grandma had written it for a (similar) situation in the past and it was passed to her and she thought it was time for her to actually give it to someone (Sora).

 

If you mean the, "Thinking of you wherever you are........" -Kairi, then the only reference I know from the game is when she puts the letter in the bottle and sends it in the ocean for "the boy she can't remember" (Sora)

I don't know if she came up with it or her grandmother told it to her. I guess it's up to the gamer to just imagine the possibility. My opinion, she probably came up with it.

 

It says Kairi at the bottom

I'm gonna take a guess and say that Kairi thought of it. If her grandmother had told it to her, then I assume it would have been referenced in BBS.

 

I'm thinking that kairi made it, since she said that she wrote it the day before, and I don't think that's something her grandmother told her. That, and it was about her and Sora, so probably no, I do not think her grandmother told her it

 

The fact that her name's at on the bottom of the letter, she narrated it, and it makes obvious references to her and Sora makes it pretty obvious that she wrote it.