If you have a Pixel 2 or a Nexus 6 you can have the latest version of Android P right now. It is not being “pushed” to phones but can be manually installed by going to settings>software update and you will be offered the update. I have had it for 3 days now . This is the follow up to the previous version that was a developer preview which I found pretty stable. This version has been 100% for the past 3 days anyway. I do not see any new options in settings regarding hear aids. This is not the final consumer version and will have updates added, supposedly, weekly if not more often. Some of the other new options are present but not activated or must be manually turned on. Not suggested that you install the update if you want a fully polished, totally stable OS, although I have not had a single glitch.
If you are considering buying a new phone to use any of the new features in Android 9 §. I would suggest you strongly consider a Pixel 2 from Google. Any other brand of phone will be dependent on your carrier updating it to Android 9. Some carriers take over a year to do so, if at all. Pixel updates come directly from Google(th maker of Android), not from carriers, and generally get updated the day they are available. Up dates are also guaranteed for 3 years on Pixel 2’s. I have no connection to Google or Pixel, although it may sound like it!