For starters, I would be concerned about any theory Nancy Lieder supports. I believe she appears in the video you posted. I mean, after all, the woman claims she was contacted by a race of aliens, called Zetas (short for Zeta Reticulans, aliens from the star Zeta Reticuli), who implanted a communications device in her brain so they could keep her up to date. When Hale-Bopp showed up, she claimed "The Hale-Bopp comet does not exist. It is a fraud, perpetrated by those who would have the teeming masses quiescent until it is too late. Hale-Bopp is nothing more than a distant star, and will draw no closer." I'm assuming you're all old enough to have actually seen the tail with your own eyes. Also, she was convinced that this planet was actually supposed to show up in 2003 - so convinced she told all her followers to put down their pets, which they did.
As far as the theory itself goes, it proposes a very large planet that's on its way towards us. Alright, but if it's going to reach us any time soon, why can't we see it with the naked eye, as we see Jupiter? The video seems to imply that perhaps we're missing it as comets have been missed, but we're talking about a massive planet, not a comet in this case. And as far as any of that NASA keeping it hidden trash, they can't blot out the sky. Amateur astronomers around the globe should be identifying it.