The answer is clearly in the name.
It doesn't matter what you call the device when you are not using it. You can call it your boat hook or your outrigger or your whisker pole, as soon as you use it to fly your spinnaker it is a spinnaker pole.
A whisker pole is a pole you use on a jib. If you use the same pole on a spinnaker it is then a spinnaker pole and must be measured, reported and is subject to spinnaker pole penalties.