That video is of such poor quality that it's hard to determine anything from it. Yes, a tractor hit a barrier, flipped, and caught fire. Unclear why it hit the barrier. Did the driver intentionally run it into the barrier? Did the police shoot him and then the tractor continued on into the barrier?
Not saying it wasn't the simple explanation, but that video is not really evidence of anything either way.
Erm, you are requiring the kind of rigor that is needed to establish someone's guilt for establishing someone's innocence. Innocence is the null hypothesis.
The quality of evidence supporting the rumor that the person had been shot by the police was extremely sketchy and the evidence that is available points to the incident being an accident.
Not saying it wasn't the simple explanation, but that video is not really evidence of anything either way.