Doc covered it pretty well.
But I think I would make an all-out effort to try repair the wires at the axle because pulling wires thru the motor is a major PITA.
Since the motor still runs, one can hope that the actual metal wires are not damaged.
Given that you are going to splice in a connector, I would cut the cable about 4 inches from the axle and carefully remove the damaged outer sheathing. Since you will have bought various sizes of shrink-fit, cover any individual that have any damaged coatings w/ the smallest shrink-fit possible. Then slide a long piece if shrink-fit over the bundle and try and get it up and inside the hole. You might even use 2 or 3 pieces. If you mess up and have to cut off any shrink-fit, be careful you don't cut any inner wires. Then I would go to the hardware and buy a length of spring that will slip over the cable, but at the same time, you can stuff one end into the axle opening. Lastly, buy one of these as I think this size fits your motor;
http://www.ebikes.ca/shop/electric-bicy ... acket.html
Splicing and soldering is not rocket science, but takes some practice. You will have enough length in the 9-pin extension that you can cut off some pieces and practice.
Basicly w/ the shrink-fit it works like this;
You will have to expose enough length of the inner wires to be able to slide a piece of shrink-fit long enough, that when you finish the solder joint, it will be long enough to slide down and cover the area where you soldered. The same is true for the outer sheathing, enough length of sheathed(untouched) cable to fit a piece of shrink-fit that went slid down, will cover the un-sheathed area.
Hard to explain, if I could show you, you would get it in a minute.