The officer doesn’t have to mirandize the driver until he has him in custody and his environment is secured. As far as searching the vehicle he asked the wife if she was taking possession of the vehicle and then asked her if he could look inside. If he had found something he would have been covered by the video.
The officer doesn't have to Mirandize him at all, unless he begins a custodial interrogation. He ought to, sure, once things are secure. One would hate for the suspect to confess that he was the weedwacker serial killer on the way to the jail, and then have that confession overturned because the officer had not receited the mantra handed down by Chief Justice Warren.