Have you used an iPad 2? Much better on iOS 9 than iOS 8 or iOS 7. Period. Just as an aside it would be better to stick to the topic and not the poster.
Saying it is better than iOS 7 is absolute rubbish. My father's iPad 2 is still on 7.1.2 and it is BLAZING FAST compared to iOS 9 on an iPad 2. iOS 7 renders animations properly 95 percent of the time. iOS 9 is lucky to do it 50-60 percent of the time. In iOS 7, apps pop open straight away, everything is faster, pages stay loaded in safari (more than in iOS 8 or 9), apps remain open in multitasking (are than iOS 8 or iOS 9).
I regrettably managed to accidentally update my main iPad 2 to iOS 9 and I hate it every minute I use it.
I think the point of this thread is that Apple promised improvements in iOS 9 and many of us have found the opposite and thus have provided evidence of slower performance, lag, stutter etc. I think every single one of us accept that people perceive things differently, but nobody here who claims iOS 9 is better, faster, more stable or anything that Apple promised has shown proof.
Where is the comparison of iOS 7/8/9 on any device that shows better performance?