I believe you still have to be registered in the appropriate province to practise physiotherapy. That is the same whether you are in private practice or health service. And you have to pass the competency exam before you can get full registration to practise.

And if you are a foreign trained PT you still have to have your training assessed and accredited by the Canadian Alliance of Physiotherapist regulators before you can apply to sit the exam, so I really don't imagine the process to be any shorter if you are going into private practice, even if it is your own business.