I wrote, "it is already 9:00," and was told I had used the wrong word.
schon (already or yet) may be replaced by "noch" ? in that case when schon means yet.
Noch means 'still' and schon means 'already', they are very different.
It is already nine o'clock. = It is already nine of clock. ?
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"
Why is it is nine o clock not accepted
You need to address the "schon" in the question, so you should have had 'already' in your answer.