What openings do you play? Those are the openings that you'll find easiest to teach, the ones that you yourself somewhat understand. They'll feed off of your enthusiasm for the opening too. You'll be able to back up what you're teaching them with the fact that you yourself play what you're teaching. They'll love that.
Also, to be quite frank, if I was at your level, I wouldn't feel comfortable tecahing anything that I didn't play regularly to any level of beginner. The last thing you want to do is teach them things that are wrong.
I'm hosting a week-long chess camp for 9-13 year olds. Much of the time will be working on tactics, end game, and strategic elements, but I do want them to have a "go-to" opening that they can build from.
Last year I did an "openings sampler" approach and it didn't work. They loved learning the names of the openings, but their opening play was still poor. Worse, they did decently on the tactics exercises but couldn't spot tactical opportunities in their own games.
So I think I'm in "Traps and Zaps" territory, where I'll teach one or two openings, and emphasize the tactics that tend to pop up in those openings (like Pandolfini does in his traps and zaps books).
But which openings?
I'm considering the Caro-Kann, because playing 1...c6 isn't a terrible idea no matter what white does. Lot's of young players start with the CK for this very reason.
I'm also considering teaching 1...e6 and then moving to a French or Dutch depending on what white does.
What do you think?