score:12
We do not know that the third hour was exactly 9:00 AM - that is an estimation for the purpose of providing an understandable translation.
The Jewish day started at dawn and ended at dusk. There were 12 hours, which were each 1/12th of the stretch between dawn and dusk. (More info.)
For simplicity, if we consider dawn to be roughly 6:00 AM, that would make the 3rd hour about 9:00 AM.