Just got back from Cuba 2 weeks ago, you definately need a passport to get in. You can fastrack it for 130$ and you'll get it in about 10 days.
Here's a tip that will save you time, fill out your form online:
http://www.ppt.gc.ca/can/index_e.aspx
When you get to the passport office you won't need to wait in line, I was in and out in less than 10 minutes.