iOS 8.4.1 update was important
yep - lots of security bods predicted that the combination of known security exploits (both crash/data execution and execution of unsigned code) would lead to exploits.
https://support.apple.com/en-au/HT205030
Of course we can't be sure, but my guess is that the problem is 8.4 specific - but the 8.4.1 release / fix was not out for long before iOS 9 replaced it - and for some of us who don't want to be guinea pigs for a major new release, that's a problem.
Biting the hand that feeds IT
