Hello All,
I have had the same iPad problem. IPad2 used with Pages every day. Suddenly almost unusable, a real problem if you are a writer!
I followed the instructions on this link first of all. http://osxdaily.com/2015/09/18/slow-ios-9-speed-up-tips/
It helped for a while but soon slowed down again.
Then I turned off all the notifications on every app, stopped iCloud sync for everything accept Pages. (I only use really use Pages on my iPad and have a iMac\iPhone for everything else so its not a big problem for me...but it does rather negate the reason for having an iPad in the first place)
Having done all of this, I deleated as many apps as I could that I do not often use....far to many to admit to....and then Hard Reset the iPad
REsult! The iPad now much faster than it was and nearly back to normal. However its nowhere near as useful anymore and I'm rather disappointed that Apple have not sorted it out themselves. I've yet to see any acknowledgement from them that there is even a problem.
I await iOS 9.2 to see if I can turn everything back on again witout Pafges becoming useless....
Hope this helps