As per the changelog, Oppo A9 (2020) is getting a fix to the issue where the user was unable to add facial information for screen unlock. It is also getting performance smoothness in several scenarios. Oppo has fixed the Bluetooth earphones volume issue and a crash issue when making phone calls in several conditions.   The new software update brings optimizations to bokeh effects in portrait mode. It also improves the photo clarity when taken using the ultra-wide lens and fixes the issue “where photos taken against the light in Night mode were dim”. 

If you’re Oppo A9 (2020) user and have not received the new update yet, then manually check the status by navigating to Settings » Software update.

Changelog:

System Provides smoother system performance in certain scenarios. Fixes an issue where you couldn’t add facial information for screen unlock in certain scenarios. Communications Fixes a volume issue with Bluetooth earphones. Fixes a crash issue that occurred when you made phone calls in certain scenarios. Camera Fixes an issue where photos taken against the light in Night mode were dim. Improves the clarity of photos taken using the ultra wide lens. Optimises the bokeh effect in Portrait mode. Security Integrates the August 2021 Android security patch  to enhance system security.

[source]

Oppo A9  2020  gets August 2021 security patch and camera improvements with the new update - 2