This is probably an obvious one, but I can't find it, or any mention of it.
In v8 I had it set up so if a policy failed for one reason or another, I would receive an email notification. It would seem that since upgrading to v9 I've lost that. I still receive notifications for when certain Smart Groups change, so I know the email config is working.
I have "Error occurs when policy runs" ticked in Notifications, and the policy is showing as "Failed" in the logs.