“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?
Roughly. It’s slightly offset later than that because I start late, though. Official work week here is 35h, which is usually more like 38h (with extra time provided as extra leave days).