It's more like, ''Home, James!" referring to your *driver* to get a move on. I first heard my mother coin? this expression at the age of 8. I say 'coin' because i donot know from where it wast derived. We didn't have a driver, nor know any fellows named James. It was more like, let's go. I use this expression when I'm in the car, ready to get a move on, speaking to the driver who may or not go by the given name James. Luckily my new driver is actually named James so this isn't a problem.
Home, James! I'm done with this shopping establishment and would like to take a nap.