Looks like they're rolling out 11.2.8.8 for the device : OxygenOS 11.2.8.8 for the OnePlus 9 and OnePlus 9 Pro - OnePlus Community
Not seeing anywhere that it will get a full build, which is unfortunate since it's a PitA to update with an OTA when rooted and having a ton of mods.
Edit:
Changelog from forum in case you don't want to bother clicking the link:
Fixed known issues and improved stability
Not seeing anywhere that it will get a full build, which is unfortunate since it's a PitA to update with an OTA when rooted and having a ton of mods.
Edit:
Changelog from forum in case you don't want to bother clicking the link:
- System
Fixed known issues and improved stability
- Ambient Display
- OnePlus Store