Any such thing can easily be created with simple circles animated to give the illusion. Trying to even use CC Sphere only makes your life harder. Simply seems like you are merely looking for a "Which button must I press?" solution due to your lack of experience. Perhaps you should try and find a tutorial on how to draw a "crescent moon" or "sphere with shadow" e.g. inh Illustrator and apply the techniques found there after reading the AE online help on things like using track mattes, masks and shape layers for all sorts of mutula cookie-cutting and animated shapes. It realyl only boils down to that.