Can I use the same Supercell ID for all my Supercell games?
Yes you can.
After creating a Supercell ID in one Supercell game, you can simply log-in in another Supercell game to start saving that game's progress to your Supercell ID. You can have all your Supercell games save progress to the same Supercell ID.
Please note that you can only bind one game account per game to a Supercell ID. To save several accounts in one game to Supercell ID, you must create several Supercell IDs.
Below is a video explaining how Supercell ID works across all your Supercell games.