one of my friends is in middle-management at an accounting firm... he got a talking to from his boss once ever being ~10 minutes late twice in a week.
I'd go nuts.
That's how it is at my job. You're expected to be there when you say you will be. They're very flexible if you ask in advance, but if you agreed to something as trivial as start time and can't manage to get to work on time, what does that say about everything else you do?
I guess it really depends on if you work solo or as part of a team. If other people are depending on you, you need to be there on time. If they need you for something that can't wait, being late it affecting more than just you.
I guess every company is different. Who the hell would want to come in at 9 though? Jesus.