So here's how it went.
After installing 3.9.1, I found that the menu bar icon would no longer launch 1P, and the "Launch 1Password App" from the Safari extension would start 1Password, but not display it (I could see it in my dock - but no GUI was visible unless I clicked on the icon).
I then went to the safari extension and locked 1P. After that, the menu bar icon started to work as expected - I can open 1P successfully from there, even after unlocking. So that all works fine now.
But the "Launch 1Password App" from the safari extension still starts 1P running (shows in my dock with a blue dot under it), but does not show the GUI until I click on it in the dock.
I should add I don't really care all that much, since I don't use that button in the extension anyway, but I thought I'd at least bring it up...seems like there might be a bug somewhere.
update: using safari extension 3.8.6