Sweet potato sprout

You have 2 options. Keep them somewhere cool so they hopefully stay roughly as they are till early spring and the days are lengthening, then get the sprouts to grow. Each sprout would form a new plant. Or try planting now as you say and hope it either keeps growing through the winter or, if it dies back, has formed new roots to start off with next year. If you have a few, you could do both.
I've had mixed results with sweet potatoes. Outside one year they did nothing much. I think I got enough roots to taste what they were. Another year I grew them in the polytunnel. They grew well like melons or squash but I didn't get many as some rats took a fancy to them. The following year, one of the few I harvested started sprouting in the spring and I got several cuttings of it before giving it away for someone else to get some plants. That year I got a god crop. The year after that I tried to get 2 of my roots to sprout but they rotted instead. I haven't tried them since.