leavining agents usually involve yeast which when mixed in water then added to a flour base wil increase the volume because yeastdoubles and even triples in size due to the fact that it is a living...
Most cream puffs do not use a leavening agent. The "shell" or "crust" of the original cream puff uses plain flour and salt, similar to a pie crust. You generally do not want to use a leavening agent...