Yes, the Canada Visitor Visa has been open for all vaccinated tourists since September 7, 2021.
If you want to prolong your stay in Canada after six months, you can apply for a visitor record which will give you a new expiry date. You must apply at least 30 days before your visitor visa expires. You apply online on the Canadian government website.
The Canada tourist visa processing time varies from country to country and whether or not you're applying from inside or outside of Canada. For example, the Canada tourist visa processing time can be approximately four months for a person applying from India.