Apple Watch and freestyle libre
Can you scan your freestyle libre with the Apple Watch instead of using your iPhone? Without any other devices to connect them
Apple Watch
Not directly as far as I can tell. You'd need a 3rd party app.
Doing a quick google search I came saw this app.
https://www.ambrosiasys.com/glucose-monitoring/
Note: I have no knowledge of this app or even if it will do what you want, I'm just following basic search techniques.