If you are travelling outside Canada the simple answer is yes. There are circumstances where a special drivers licence might be OK but honestly for the small cost of a 5 or 10 year passport it saves a lot of hastle.
Passports for Children
“All Canadian children, from newborns to age 16, require their own passport to travel. Children may only be issued a passport with a maximum validity of 5 years. A child’s passport remains valid until it reaches its expiry date, even after the child turns 16.” You can read more about Canadian passports for children on the Government of Canada travel web pages and they more excellent advice about travelling with children