We're not communicating re- read my highlighted reply. IF the clock was improperly hung, If its hanger is no longer in the wall, Contractor NOT LIABLE
Shouldn't take to much to establish either way

I am a roofing contractor. As soon as we are awarded a job, a letter goes out to the occupants. Among other things it tells them to remove anything valuable or fragile from the walls and ceiling to avoid damage if it is knocked loose by the vibration and pounding.

Most people don't automatically know this. A smart contractor will give them written warning both to protect the client and to protect himself. It wouldn't hurt to very politely ask him for compensation and see what he says. Maybe he'll just pay it. If not I probably wouldn't make a big deal out of it, and count it as a lesson learned.

Let's assume it was hung up properly. What should the contractor have done, and where was he negligent?

If it was hung up properly, it should not have JUMPED off the wall. There are TOO many unknown variables for either of us to answer.
We can P back and forth but it serves no purpose

i have had my coo-coo clock rung hard several times, but not knocked off my wall.

must've used good contractors 🙄🤣🤣🤣

Most likely talk with your insurance carrier. Most likely they haven’t closed the claim. Worth a try.