I don't use or like Game Center. I'm signed out. After installing IOS9, I found I was signed back in. Signed out again. However, whenever I launch a game, a Game Center pop-up appears urging me to sign in. With IOS 8, this would stop after 3 times per game. There doesn't seem to be a similar rule for IOS9. Yeah, I also have Game Center notifications turned off. PLEASE Apple, free us from this Game Center harassment.