What does this simple rebus mean?

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

What does this rebus puzzle means ?

Usually, a boxing match consists of twelve rounds. In a particular friendly match between two heavyweights, the match was finished in the ninth round itself as one of the boxers knocked out the other one.

But, in that fight, no man threw even a single punch.

How can this be possible?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Which letter of the alphabet has the most water?

What does this mean?

CCCCCCC

Can you identify the Oscar-winning movie from the rebus below?