As you can see in the screenshot above, for some reason the displays on the iPhone 6s has been zoomed in, and not in the regular way. This has been zoomed in where the sides of the display has been cut of, kind of like the content was not optimized for the display/resolution of the iPhone 6s.
This bug seems to mainly affect native apps like Wallet, Weather, Watch, Calculator, and Health apps. It has been advised that doing a clean install of iOS 9 on the iPhone 6s will resolve this issue, but if that was the case, restoring from backup would have been kind of a waste, right? Some users are reporting that turning on Display Zoom in the settings will fix it, but this also means that it will result in the entire phone featuring a zoomed in look.
According to some who have the iOS 9.1 beta, they claim that this has been resolved in the beta so we guess we will have to wait until then to get the fix, or hopefully Apple will release a fix for it before iOS 9.1.