But 3.9 is no longer new. If you're still on 3.8 you're running out of time to upgrade as official support is ending next year.
The project has also been backported to 3.6+, so you can still use it if you're stuck on a legacy/unsupported version.
See https://www.python.org/downloads/ and https://pypi.org/project/backports.zoneinfo/