Unknown error occurred (9) attempting to restore iPhone 11. Please advise.

I attempted to backup my iPhone 11 via iTunes.

However, it also attempted to update the IOS on my phone.

When I returned to my laptop to check on progress, the update had failed.

No whenever I try to update or restore, the "An unknown error occurred (9)" message is displayed.

I cannot call Apple support as my iPhone is out now of service due to the problem detailed.

Please advise.