APFS Snapshot com.apple.os.update-... 8.9 GB disk1s1s1

As the name of the snapshot suggests, this is a pending OS update that will be installed on the next reboot. Sometimes macOS may even be booted from that snapshot.

The only APFS snapshots you can remove are any backup snapshots or snapshots you create yourself, but you do risk causing a problem with the backups if a backup snapshot is removed before the snapshot has been successfully transferred to external media.

View APFS snapshots in Disk Utility on Mac - Apple Support

It is best to leave alone everything outside of the "/Users" folder as everything outside is considered a system area.

Assuming you are referring to the sealed snapshot of the System Volume, No. Your Mac won’t boot without it.

What benefit do you imagine you will get from deleting it?