In the years I've been around, almost ALL the top pros have missed easy (hangers) shots at one time or another. And I mean all of them. Every one can tell you a story about an easy miss at a critical time.
By the way, the strangest thing about Varner's missed Nine ball in the U.S. Open is what Sigel did afterward. The Cue ball froze to the Nine, and Sigel could easily have played safe, hitting the Nine thin and leaving the Cue ball down table. Instead he just thrust his cue at the Cue ball and sent both balls rolling around the table. I mean it was a completely amateurish shot by one of the all time greats. He had a major brain fart, and it's all on tape.
One that stands out in my mind was in the Finals of the Disneyland Open in 1986. The match was between Danny Medina and David Howard. First prize was $8,000, a good purse for that era. The match went hill-hill and David was all set up for the win. He only needed to make the four ball in the corner and let the Cue ball roll a foot or two for easy position on a billiard from the Five to the Nine which was sitting an inch or so from the middle of the side pocket. The Five ball was inches away from the Nine. It was unmissable. Any amateur could make this shot with no problem. Just hit the side of the Five ball anywhere.
David plays perfect position and gets down to shoot the easiest winning shot of his life......and miscues. Hello! So anything can happen when a player loses concentration for a moment. Efren, Buddy, Hopkins, Archer, Swanson, Sigel, Earl, Varner and the list goes on and on. They have all succumbed to blankitis, where all of sudden they forget where to aim.
One other story that I like to tell in the same vein. Buddy breaks and makes a ball. The Cue ball freezes to the One. We've all had shots like this, where we hit the ball thin and go down table for a safe. Well Buddy gets set to make a very thin hit on the One and play safe. I'm refing so I stand close to watch the shot. Only one problem, Buddy aims a little too thin and fails to hit the One. He actually shot away from the ball. So I call a foul. Buddy is livid. He knows he has fouled, he is just embarassed that I would call it on him. He tries halfheartedly to protest, but I look at him and say "Buddy, you never hit the One". Buddy shrugs his shoulders, makes a face and just walks over and sits down.
He probably doesn't like me telling that story, but I think it's funny that the great Buddy Hall would make an amateur mistake like that.