Who knows? Most humans don't know how to exercise their will when alive, nor do most have free will but are enveloped by their own fear and thus impotence to act. Why would they be different as spirits?
On the other hand spirits are free from those negative emotions, if they choose to be, and so would be free. As always it is probably an individual process, something which is unique to the individual spirit.
The first question we should ask is what is a spirit- someone who is now residing in the afterlife, an echo of energy, memories which have taken form, or husks- shells which have taken the form of loved ones in order to gain some form of existence......no one knows, there are only theorys. Anyone who tells you they know for certain is lying- they THINK they know for certain, and that's good for them. Personally I like to think from all angles and accept all angles as equally true until I come to a position, by myself, whereby I can eliminate some of the angles.