Rollout schedules are a guess at best. They more often than not change.
Every area should get 1.9 by the end of September (my guess).
I have yet to see a comprehensive list of features in 1.9.
Here are a couple external threads that may offer you some of what you want.
Is there a roll out schedule for 1.9 and is there a list of features that are in it?
Release notes from the original 1.9 rollout. Not much has changed in 1.9a
There are no new release notes for 1.9a that I am aware of.