Clash-of-clans – Won’t let me connect the clash of clans account to the iOS from android

from https://productforums.google.com/forum/#!topic/webmasters/XTmiHxe-VsI

Log into the google+ account, select the "Home" drop down in the upper left hand corner. Select "settings", Scroll down to about half way down and select "Manage apps and activities", Select the edit (pencil) tool for clash of clans and select "disconnect". Make sure you check the box that asks about erasing all activities for this App. It takes about an hour for Google to erase all data for the app, but after that you can then re-connect with the account you want to use.

and another one http://cocland.com/tutorials/removing-clash-of-clans-from-google-account

This was not an easy thing to track down via Google or even clicking through my Google+ account menus. Hopefully this may help others.

No, if you are logged into Gamecenter on the device you want to keep your game save for, your game should be safe. If you want to delete the account on the other device, then you should just be able to log out of your Gamecenter, re install clash of Clans, and have a new account without damaging your other account. Hope this answers your question!