Steve,
When up in the Flinders about 18 months ago there was a gentleman giving tours of the sky and a look through his telescope so I took the family out for a look. Without putting any pressure on you the presentation was very good and went something like this.
Start with a visual tour of the sky.
Ask them what they can see. Find out what they already know.
How many planets are there? How many can you see tonight? (Don't forget to count Earth). Even if you can't do Jupiter through your telescope, point out where it is.
Talk about the constellations that you can see. Crux is a must. Point out the bright stars in each.
Show them where the milky way is - this is OUR galaxy.
If you can see them, point out the LMC & SMC.
Even if you only get half the class to come thats at least a dozen kids plus parents. Not a lot of time for each at the scope so you won't need too many objects lined up to fill the time.
I would suggest one of each category. This will take more than enough time to fill the attention span of 9yo's.
A double star. - Alpha Crux
A coloured star - Betelguese
A globular cluster - 47Tuc or omega Centuari whichever you can see
An open cluster - Jewel box, M45
A bright nebula - M42
Finaly blind them with the moon
And tell them to bring binos if they have them.