The most common and most likely answer to this crossword clue is the 9 letter word SUBJUGATE
I've seen this crossword clue in Financial Times
S
U
B
J
U
G
A
T
E
More clues leading to the result SUBJUGATE
Buddy explains!

The straight part
We know that "Crush" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case crush = subjugate.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SUBJUGATE mean?
SUBJUGATE verb- To forcibly impose obedience or servitude upon.