“The 9[am] to 5[pm]” is a common term for one’s regular job, on the basis that normal people start work at 09:00 and finish at 17:00. I’ve worked a few jobs and closest I’ve ever gotten to this is 08:00 to 17:00, which I gather is standard.
Are there real jobs where people actually start at 9 and finish at 5?
1 hour lunch means you are expected to leave the office (or at least not work). Some countries get really strict about a one hour lunch break where you don’t do any work and so it is carefully enforced there.