If someone told me they'd be there 9-9.30 I'd expect them at 9, because that's what I'd do myself I'm having to condition myself out of that though and remind myself that other people aren't as highly strung as me 🙈
I live in Germany and generally I find people are pretty punctual. My daughter had a birthday party recently and I'd put 3pm on the invite. All 12 kids arrived between 3 and 3.05 🤣🤣 And the 3.05 ones were probably only "late" as they were down the garden path waiting for the 3pm arrivals to get their shoes off and get out of the way
I have one "friend" who would turn up at 11 (or not at all) but that's a whole other story.....