Pure conspiracy theory that defies the laws of physics. It just isn't possible, regardless of whatever may be happening on Earth.
Such an object so close to Earth would be easily visible to the naked eye. A planet (such as planet X) would create noticeable effects in the orbits of the outer planets. Some claim that the object has been concealed behind the Sun for several years, but this is actually geometrically impossible. Photographs showing planet X by the Sun are, in fact, false images of the Sun created by reflections within the lens of the camera.
If this theoretical object's orbit were as described, it would only have lasted in the Solar System for a million years or so before Jupiter expelled it long ago. To maintain the theorized orbit, it would have to travel 1000 AU in two years. This means it would need to be moving at 2400 km/s (faster than the galactic escape velocity).
At that speed, it would be shot out of the Solar System and then out of the galaxy...into intergalactic space.
Conspiracy theorists make lousy scientists. They grab just enough technical info to make it sound plausible, but it's really just nonsense if you actually understand the science.
The laws of Physics are absolute and you can't talk your way around them...no matter how convincing the argument may sound to those who don't know the science.
