I have a 4s, and I have the terminal "slide-to-update" crash.
I've spent 10 hours so far, trying every fix that all the iGurus have come up with. So far, 1) all my data, photos, etc. are believed to have been deleted, and 2) my phone is a brick with a glaring "slide to update" screen. As far as I can tell, it's unlikely I'll even be able to get my photos etc. from iCloud backup, as I've read that ios9 won't allow that from older ios versions.
Interesting - probably thousands of us are stuck with Apple devices (iPads, iPad minis, Macs, etc. - there are countless reports of ALL of these (newer and older) having the identical problem, yet...not a word from Apple. Surely, the hundreds of furious users with bricked devices on this Apple forum (supposedly, monitored by Apple staff) should be a clue that there is a VERY big problem.
If it was just a minor hickup, I could live with it until a fix was offered. BUT - when a crucial (and expensive) device is rendered completely inert by a software glitch, timely recognition of the problem & assurance that Apple is working on a fix, is more than merely a nice-to-have.
Doing without a phone of any kind for several months until they come out with 9.0.1 or something is NOT an option.
So, Apple - what's your response?!?!