I think it's best you call and find out exactly what you need for traveling short-term through Canada with your Savannah. I've traveled through Port Huron to Sarnia twice to pick up F6 kittens. I had NO problem at the border at all. The border guards were not interested in seeing the kittens nor the papers I had for them...including recent health certificate (good for 10 days), proof of current age-appropriate vaccines and purchase contracts...the border people were much more interested in finding out if I was bringing over fruit, booze, or other purchases from Ontario so I could pay them duty tax...importing or exporting a Savannah for sale or purchase into or from Canada is quite different than traveling through with a pet, however.
After making some phone calls and researching, if you are at all uncertain as to how easy or not it will be to travel with your Savannah across the two borders and back, I would choose the longer route to be safe, avoiding Canada travel completely. As was stated above, you may get different responses depending on who you speak to about traveling through, and a completely different one with another person...or it may be easier on everyone to find a good and trusted pet-sitter and not take your boy along with you and avoid the possible hassles you might encounter...