Hello,
i have the same issue as you. This happened to me with an upgrade from ios 6 to ios 8.1.4 (I was forced to upgrade as a shopping app I use would not work on ios 6 anymore) luckily or unluckily my phone went faulty 2 weeks after a replacement (my 3rd replacement), it came with 8.4.0 and the battery lasted very well once all items were turned off or set to manual. 2 days and its at 40% with 1.5hrs total usage.
I thought "well 2 updates into the new ios 9 maybe it's fixed" so just upgraded from 8.4.0 to 9.0.2 and I have the same issue. I have tried reset, tried the reset all settings, as in the original post all options are OFF. my phone with 8.4 would last over 2 days, I rarely use it, however it now lasts the working day down to 23% after driving home. I have read all the forums and magazine help columns, the only thing i have not done is to restore the phone as brand new and start from scratch. the problem has been there for me since 8.4.1, my wife's phone is the same (she is on 8.4.1) and so until apple engineers can reproduce it and fix it, I am stuck. starting from scratch and entering everything again is anti-apple, I have not had to do that for a long long time. But it might be worth it, if it works.
I love apple products but now i am starting to have android dreams or even going back to windows (had to use that phone while apple repaired mine and it is 5 years old and still lasts well into the next night! It just looks so, so retro!).