The Nikon P900 is a great camera, with an 83x optical zoom it can take amazing photos and videos of the moon. However it has a bit of a failing when trying to take photos (or video) of small bright objects, like stars, or especially like Venus. Have a search for video of Venus taken with a P900, and you will see a lot of stuff like this:
These are not images of Venus, they are images of bokeh - any out-of-focus small light will give the same effect. The problem is simply that the P900 cannot focus on a small point light source. So what we are seeing is Venus blurred and out of focus. And since it's essentially a point light source it forms an "orb" shape, commonly referred to as Bokeh. It's fairly easy to duplicate, which is what I do in the above video.
The orb effect gets more interesting when viewed through a ripply atmosphere. The out-of-focus bokeh magnifies the effects of the ripples (because it's essentially magnifying a point light), and you get some very odd looking waves moving over the orb.
Many people have misinterpreted these "rippling orb" videos as actual footage of Venus, but as the video above shows, it's not.
The effect was duplicated in my garage using a bright light behind some cardboard with a pinhole in it:
This was at one end of my garage, at the other is the camera, and I held a small tealight candle a few feet in front of the camera to create the turbulence. This is similar to atmospheric turbulence (from rising warm air, especially at dusk) but on a smaller scale.
And the result is the same type of rippling orb we see in the "Venus" videos