HI Angel!
Thanks for finding us here on the Moms Panel!
I have to admit that your question stumped me and I had to consult with one of our Canadian Moms - Joanne.
She let me know that your driver's license should be fine as long as it has a photo. Valid forms of ID for adults are photo identification issued by a government agency: drivers licenses, passports, etc. For those under age 18, a copy of a birth certificate will be valid id (although in this case I think I would make sure to bring the passport, just in case). The Give A Day. Get A Disney Day
faq also has more info on redeeming your voucher, so be sure to check that out as well
Of course, to be honest, I am an over-planner and always worry about these things, so if it were me, I'd probably take my passport along just in case (or perhaps a photocopy of it along with my Drivers License). I do tend to go overboard with some of these details -- just ask my family!!
I hope you have a great trip! And thanks again for volunteering! I love hearing from everyone who is getting out there and getting involved!