Wiring hanging pool table light into outlet plug?
A couple schools of thought. First is the easiest and as far as pool tables go very appropriate and that is the old swag lamp kit. You can get one fairly cheap at your local big box store, connect a couple wires, screw in some hooks and plug it in. They already come with a switch.

If you do plan the harder route as you outlined above, think about running 14/2 Romex and concealing it in raceway. This is more attractive and safer than running a bare wire along your ceiling and wall. If you want that industrial look and want to be safer. You can run 14/2 Romex in metal conduit and mount to your walls and ceiling with conduit hangers.

All three scenarios simply need a quick dab of plaster in the holes you make for your fasteners when you move out.