There has been a lot of reports about battery life draining fast on N9 after PR1.1 firmware update, it seems like i have been hit by it as well.
Updated to PR1.1 couple of days after it became available and since then had couple of days, when for no apparent reason the battery has been totally drained in 7-8 hours. usually with normal use my N9 gets easily the day and still has battery left for half a day. Had nothing running on background, have the same setup for my accounts updates and same apps as i had on PR1.0.
I wonder could it be something on the Email app as it got fair share of updates on PR1.1 and for the first 3 days when i had no battery problems, neither non of my Email Accounts where up yet.