Running 9.0 Beta 4 in the shadowlands beta and I've configured my auras to have bindings and notice an issue I also see in Classic - the key bind labels extend far off of the smaller buttons.

I play in 4K and have my UI scaled to .85 but changing the scaling to 1 doesn't make a difference, screenshot below.

The top bar is the default aura bar, the bottom bar is an 80% action bar with reduced spacing and padding to match the aura bar:

As an update, it looks like the default UI doesn't show, or is incapable of showing the key bind labels on the class bar at all :(

Fixed in beta 5 (along with the pet bar).