A one gallon pot would be enough for the first year. Once the bines die back for the fall, you could either leave the roots in the pot or pull them out and store them in your fridge. I'd just leave them in the pot and pull the whole ball out for transplanting.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk