You would treat this as if you actually purchased the vehicle in the year. Your cost of this addition will be the amount you actually paid for the buy-out (or residual value), and you will use the date you made the buyout as your "date of acquisition". The half-year rule will apply as you have actually purchased this vehicle from leaseholder.
And yes, you would add this vehicle as a Class 10 asset.
https://turbotax.intuit.ca/tips/what-is-capital-cost-allowance-2016
