Apple has released watchOS 9.1 and tvOS 16.1 alongside the other major operating system updates with very little fanfare or user-facing features.
The operating system update cycle tends to occur in sync, so alongside the macOS Ventura and iPadOS 16.1 release, Apple's other systems got point updates as well. There aren't many changes beyond the usual bug fixes and improvements in tvOS 16.1 and watchOS 9.1.
Apple does list Matter support as a feature of tvOS 16.1 and HomePod software version 16.1. The new connectivity standard has been launched and is available to manufacturers, though the implementation hasn't been seen in products yet.
No new features were detailed for watchOS 9.1. Release notes repeat information about watchOS 9's release features, so users can expect performance updates and bug fixes.
Updates will be installed automatically, but those who want the updates right away can perform manual updates.
Open the Watch app on iPhone
Tap "General"
Tap "Software Update"
If the update is available, tap "Download and Install"
Open the Settings app on Apple TV
Scroll down and select "System"
Scroll down and select "Software Updates"
Select "Update Software"
How to update HomePod software
Open the Home app on iPhone or iPad
Tap the ellipsis and select "Home Settings"
Scroll down and tap "Software Update"
Tap "Update"
Source: Appleinsider