I'm a teacher and experienced (but non-paid!) Europe travel organizer/director/guide (the only thing I don't do is drive and cook in Europe) with no experience in Prague. Will be there for one afternoon and one full day (two nights) with my grade 9 students in March 2010. What to do , what to avoid - suggestions? I've already read Rick's books of course. Just want some other perspectives.
Wow! You are a brave man!
The John Lennon wall is a little cheesy, but also touching and inspiring at the same time. The ratio of cheesiness to inspiration can change depending on when you see it; since it's a wall of graffitti dedicated to John Lennon, it changes over time. Not far away is The Mirror Maze on Petrin Hill. It might be a little kiddie-ish for ninth graders, but some might enjoy playing Bruce Lee in "Enter the Dragon":)
We took our son to Prague last year (he was 13yo then), and we all got a lot out of the Museum of Communism. It's a small museum, and didn't take long, but will give the kids a perspective that they don't get in the U.S. (We were also in Budapast, and visited the Terror Museum there. Some of the same concepts, but different enough, that both are worth visiting.)
We also took a private tour (through a company recommended in Rick's book, Prague Guide, www.prague-guide.info. We're interested in politics and history, so we took the "Revolutions in Prague" tour. Interesting and informative, it covered older revolutions (Jan Hus' time) as well as the Velvet Revolution.
Castle Hill is the well-known place to go; we found it interesting, but not hugely so (there's actually not much of the castle istelf to be seen).
We also spent several hours visiting Josefov, the Jewish area. It was interesting and heart-breaking. At the time, and I believe it's a permanent exhibit, there was a display in Pinkas Synagogue (Pinkasova Synagóga), of pictures drawn by children at Terezin. It was very moving for all of us (and we're not Jewish). This last Spring, my son visited Washington, D.C., and went to the Holocuast Museum. His comment was that it was "nothing" compared to the Pinkas Synagogue, because Prague was one of the places the Holocaust actually happened.
I liked the castle because it was more than the castle--two churches and gardens as well. Also, great views! They may also like the clock tower in Old Town Square. It too has wonderful views from the top. They'll want to watch the clock itself as well.
First Afternoon: Castle Hill and Kafka Museum (these are both on the left bank). I didn't pay attention to any restaurants on that side of the river, but I know there is a McDonalds and a Starbucks right as you come down the hill and before the Charles bridge. The Kafka Museum is right at the base of the Charles Bridge and it seems to me that there were several large restaurants right there as well. Walk across the Charles bridge.
morning: hit the Bake Shop which is the best bakery in Prague and is really cheap, right off the Old Square, sort of north and east. You can get breakfast goods and also they have sandwiches, prepared salads, etc. for picnic lunch later if you like. Eat wandering around the Old Square where you can see the clock and statutes, and there are plenty of benches, etc. Then walk over to the Jewish quarter and do the Jewish Museum.
For lunch: go to the Bagel place that's listed in your guidebook but the name is escaping me. They have an internet cafe and a big selection of lunch stuff. Plus its big enough to fit your whole group and is cheap.
For the afternoon: take the yellow line on the metro (pay special notice to how fast the escalators are) over to Praha 5 and hit the mall - these are kids, they will love you for this. Really the people watching there is unreal and there are a ton of cheap eats in the mall (this is the same mall where the Tesco's is, in case you'd rather do takeaway food). Across the street from the mall is a multiplex movie theater - they have movies in English and Czech, usually first run. At one end there is also a really large pizza restaurant above the plaza where everyone hangs out. I can't remember the name of it, but you wouldn't have any trouble finding it because the plaza is very obvious and it has neon signs (the pizza was really good and $6 for a large...). This section of Prague is where you see the real people, not the tourists, so adds spice...