Yes, all you need is a fishy pool, hose, and the fill & drain kit.
I had a waterbed in the eighties,
and so I used one of these devices all the time to drain the bed when I had to move.
You don't need a submersible pump or anything complicated to drain the pool if you have the waterbed fill & drain kit. The adapter is shaped like a "T" (see the photo in the link below). It uses the water pressure from your sink to drain the pool.
One end of the "T" attaches to any faucet (bathroom, kitchen, washing machine, outdoors, etc.) Then the perpendicular arm of the "T" is where the hose is attached. Finally, the third side of the "T" (which is pointing down toward the bottom of the sink) has a rotating mechanism which you lock in place in the "closed" position to fill the pool. You then turn the water on, and it runs through the hose into the pool. When it is time to drain, you turn the bottom part of the "T" into the unlocked or "open" position, and turn the water on again. But now, the water is not flowing INTO the pool because the bottom part is open, and the pressure of the water creates the vaccuum which pulls the water out of the pool through the hose, and into the sink to drain. Make sense?
Click here on this link to see a better photo:drain & fill kit
You will only use the small white piece which first attaches to your faucet, and the T-shaped blue piece. The other blue piece (which you don't need) is to attach the other end of the hose to the entrance of a waterbed mattress, and obviously you don't need the water conditioner, but they are usually sold this way.
The other nice thing about it is if the water cools off too much you can drain a little, then add more hot very quickly.