Noch means 'still' and schon means 'already', they are very different.

Maybe one could say that a few hundred years ago, but as far as I know, today we do not.

I was under the impression it was "on the clock" but maybe it is "of the clock"

It means "of the clock," similar to Good Bye originally meaning "God be with ye."

"It is already 9 hours" isn't English. You have to say "It has already been 9 hours".

Es ist schon neun Stunden seit er geschrieben hat.