Here's my thoughts for what they're worth: I would first ask if the class is part of the curriculum or is it students that just want to learn about bonsai. For me, that would make a big difference on how and what is taught. Either way, I would spend the first hour or so on what bonsai is and what it isn't. You will have to engage and not lecture them. As a thought, you may want to start off by showing that short video Ryan did on Nat Geo about the Artisans Cup. After watching that you should be able to get a feel for your audience.
Think back to what it was like for you when you first got into the art. Yes, you know it all now (just kidding) but what did you need the most guidance with early on? With only 8 hours, I wouldn't move past the basics or you'll be doing them a disservice. I would have plenty of examples set up for every one to talk with you about, during breaks and such. Maybe do a repot and prune on one tree so they get a feel for what to do. Then, for those that are interested and with the program directors consent you can offer your services up for more classes. (for a fee of course)
Just my thoughts..