All the changes look good to me.

I think I saw some discussion over whether we want to backport performance
changes or leave things as they are so that people have an incentive to upgrade
to 9.12.  I don't know if that was ever resolved.

(In my opinion we shouldn't withhold fixes from any branch that don't
affect compatibility or stability, and these should definitely be backported.
I'm just mentioning it because I'm not sure there was consensus on the point.)