Delete game data from game center?

Want to Remove Game Data from Game Center?

If you backup Game Center AND the specific game app’s data via iCloud, you can manage the storage on your iDevice or Mac.

For Macs

1. Go to Apple Menu >System Preferences > iCloud
2. Select Manage Storage
3. Look for the game in your list of iCloud App Data and select it
4. Choose Delete Documents and Data–this deletes that games data from all Apple ID connected devices!
   1. A confirmation pops-up, select Delete to go ahead or Don’t Delete to retain your game data

For iDevices

1. Go to Settings > Apple ID Profile > iCloud
2. Tap Manage Storage
3. Look for the game in the list of apps that iCloud backs up data for and tap it
4. Select Delete Data–remember this action deletes all data for this game from all Apple ID connected devices
   1. A message pops-up asking you to confirm the deletion
   2. Select Delete to remove this data or cancel to keep the game data

Where is Game Center app? Now using iMessage, iCloud - AppleToolBox

Also see: Everything you need to know about Game Center - iMore

This discussion thread may help you.

https://discussions.apple.com/thread/8325448