Is there a code to play as cloud in kingdom hearts 2?

no, the only people in the game you can polay as is, Roxas, Sora and Riku a bit t the last fight, so you cannot use Cloud, although you could get the game Final Fantasy VII to use Cloud if you want him that much

Wrong, if u have a cheat device such as GameShark, codebreaker or action replay you can find the codes (google or YouTube it) and that will allow you to play as different characters, beware you might not be able to use reaction commands or magic (it will cause the character to freeze).