As Moondog says, luggage usually arrive very quickly in China.
While the left luggage area is easy to find, I would not bother and just leave them in the trunk of the car. Taking a photo of the car and plate is a good idea if you take a taxi. With a reputable driver who treats his clients like friends such as DingYi, he may be a bit insulted so better tell him that you want to make sure you can find the car in the parking lot, not that you are concerned that he will leave with your luggage.