^._.^ Congrats on the offer! I can't really describe the experience of year 9(most of my friends have said it was the best time of their life) because I'm a year 10 entry student. But I will say school is super chill and there are plenty of amazing people with their own different strengths and passions. The timetable is a bit confusing and they do a lot of extra things compared to most schools. But after a few weeks you'll get used to it.
There are a lot more things about the school, but you should experience that when you get there!