I’ve worked from 9:15 to 4:30 at one company and 9:00 to 5:00 at another. Both also have mandatory on-call (24/7) on a weekly rotation. The latter also mandates that releases be done at 8:30pm.

Both companies have daily meetings (standups) at 9:30. The latter also has frequently has meetings at 9:00.

Just my experience.

Edit: Oh, I should mention. When I started at the latter place, my boss was like “what will your hours be?” and I said "how about 9:00 to 4:30?” And he was like “cool.” Then a couple of days later, he was like “we need another half-hour per day.” And I said “ok, how about 9:00 to 5:00?” and he was like “cool.” And then a couple of years later after my boss had left the company, my boss’s boss said “so… you’re supposed to be working another hour a day… I don’t really care because you get your work done… you must have had a special deal with <boss who had just left>, yeah? Well, even if you don’t need to work that extra hour, do log an extra hour a day, please.” Lol.