Just saw that 9.1 (13B144) is available (the latest as of a few days ago was 13B143). It won't show up in Software Update, but if you connect your iPad to iTunes and select Restore, your computer will download the 13B144 build and install it. Don't forget to back it up ahead of time! I'm guessing this is to address the "won't wake from sleep" issue.
It has been out for a few days now. I had the wake from sleep problem so I decided to try a restore with that new update and I have not had the wake from sleep problem since then. It could just be a coincidence, of course.