New car, when does insurance start?

Hello, yesterday in the car dealership bought a new car, that car dealership will hand me the car on 4.9.15, at least for this day the pick up is planned.. the car dealership will take over for me the registration, of course I must now look for insurance for the car, and because, the insurance code informs. My question is now, I have to start the start of the insurance directly for the car dealership to register the car or can I register the car insurance to start the 4.9, where the car is picked up by me? Can you still register the car? Thanks for the help