I have an iPhone 5S, battery life has been ok on iOS 8, I tried iOS 9 and battery life has been horrible, it would last for 2 hours and with a maximum of 3 hours compared to 6 hours on iOS 8.4, iOS 9 is a great system, it has some lags that could be fixed later, but now I'm feeling that my iPhone is counting down the battery percentage, while writing this post which exactly wouldn't take more than a minute, I lost 2 %, I went straight from 96 to 94% that fast, I hope apple fixes the issue like it fixed the heating up issue that has been around with iOS 9 betas. It's really an annoying issue even though im not on neither Lte nor 3G, i get wifi like just for 10 % of the whole day. If u experience the issue I have on any apple device feel free to tell me in the comment bar