It works here. Android Auto updates usually are not contingent on HU updates, which is the entire point.
One thing to keep in mind is if you are not actually enrolled in the beta builds on the Play Store and just downloaded the beta apk only, that is not enough. You need to be enrolled in the beta program to see the new features.
At this very moment, the beta channel is closed to new sign-ups. I thought the APK install would do the trick with beta version but obviously it did not.
There is no option but to wait for the official rollout through Play Store