Grade 9 level in Cambodian International School.. HELP!

[ortano]

Hi guys just needing some advice. I have a job interview tomorrow and they're wanting me to teach a class in the morning and see how it goes, fair enough, but he couldn't tell me their level.
They're 14-15 year olds and I am to teach them anything; vocab, grammar, conversation, etc. but that is all the information I've been given.
I've only ever taught in 1 school in Thailand, I taught 10year olds. My girlfriend is now teaching 1 graders in Cambodia and their english is so much better than the level I taught, so these 9th graders are going to be really good.

Anyone have any advice on what material to use or just how much they're going to know, I don't want to rock up with something too hard, or probably too easy.

Cheers.