2) Better Battery Performance
There was no clear battery saving mode in Apple's iOS 8 to save battery and user were left with the options of switching Off their Data ,Wifi or reduce brightness etc for conserving the power.
But with iOS 9 introduction of “Low power mode” user can save phone's power for at least three more hours of typical usage claims Apple.
Apple also claims that the iOS 9 will provide user with additional one hour of general usage then its predecessor iOS 8.This Improvements in battery departments will be loved by the Iphone user as now their phone's battery charge will last longer.