How can I transfer or link my Clash of Clans account to an Android device, from iOS?
You don't need your Game Center user and password —which in any case is usually your Apple ID and password; you can link devices in-game.
From the Supercell support site, specifically &quot;Transferring your game to another device&quot;:

iOS &gt; Android or Vice Versa
First, make sure the game is installed on both devices, keeping them both on-hand. Use the “Link a device” feature in the in-game settings, and then select “Link a device” on both. Follow the on-screen instructions to complete the transfer.