iOS 9.3 on A7 iPad is pretty good, minus the task switcher. If there is a blurred app in the app switcher (4 app cards on screen) the animation when going into an app from the switcher will stutter. However going into the switcher from an app is smooth, it's weird.
Overall, iOS 9 is smoother than iOS 8 I would say, but generally just slightly slower in loading things or responding sometimes for example. But yeah spotlight pull down is smoother in iOS 9.3 than iOS 8, I compared against a friend's iPad Air on iOS 8.3, my iPad mini 2 is on 9.3.1. Control Center on the lock screen/open folder is perfectly smooth now on iOS 9, that always stuttered on iOS 7 and 8. Control center is smooth over a portrait keyboard but stuttery over landscape keyboard. Before it always stuttered no matter the screen orientation. One thing I can say, opening folders for the first time is TERRIBLE on iOS 9. It had issues on iOS 8 but not this bad. Also going back to the home screen after using an app for awhile is sometimes pretty choppy. This happened in iOS 8 as well, though. iOS 9 just may be a little worse but I can't exactly remember how bad it was before just that it happened.