Just upgraded to 2.9 yesterday (12/20) on http://www.feedthehabit.com. Had a post scheduled to publish this morning (12/21 @1:00am) and it didn't work. So, I re-scheduled it to post at 10am... still didn't work.
Re-scheduling to 1am 12/22 to test once more.
Looking at it, there were several enhancements to this functionality for 2.9 and it appears to be buggy.
Anyone else having these issues?