I agree with Karl. These sentences have different meanings, and the 'it' has a different meaning in each of these two sentences. In "Don't pin it on me!" , the 'it' refers to the blame. It means "Don't blame me for this" (meaning the fact that the camera has gone missing). In the expression with 'plant', the 'it' refers to the camera. If you said 'Don't plant it on me!', you are telling someone not to literally hide the stolen camera in your bag (or desk, or room or wherever) in order to incriminate you. This seems very unlikely, as the whole point about planting incriminating evidence on a person is that this is done without their knowledge! If you want to say "Don't accuse me of doing this", the phrase you want is the first, not the second.

"Don't pin this on me!" is correct. "Pin" is used to put blame on a person. "Plant" is used when physical objects are put into another's possession. In your example with the stolen camera, if the camera was put into your bag, the camera was planted on you. If you get caught and get into trouble, the guilt is pinned on you.

Yes, you used both phrases correctly.