No such thing as a Nikon P9000 .... there are the P900 and P1000 model cameras, which come with a non-detachable lens, which can be zoomed to extreme focal lengths, included. These have indeed a good reputation for a viable solution for moon or even basic planetary shots, however these - being NON-interchangeable lens cameras - would be an exceptionally BAD fit for attaching them to a telescope or dedicated telephoto lens.
People have succeeded getting recognizable pictures of the ISS with this camera - eg
, though there might be significant planning and skill involved.Photography-oriented telephoto lenses for DSLR/DSLM cameras of that focal length are a) rarely cheaper than a P900 if you want them to have even the resolution the P900 provides, b) be significantly harder to use - affordable ones are going to be bulky and heavy and have no image stabilization or autofocus, these would take a lot of experience in handling tripods and manual focus in the dark. There are eg cheap 650-1300 zooms available for $200ish, resolution is questionable though and all the handling difficulties I mentioned apply in full - and these are only at all useful with an interchangeable lens camera, NOT a cellphone.