The most common and most likely answer to this crossword clue is the 9 letter word DISSIPATE
D
I
S
S
I
P
A
T
E
Buddy explains!

The straight part
We know that "drive away" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case drive away = dissipate.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.
Crossword Answer definitions
DISSIPATE verb- To drive away, disperse.
- To use up or waste; squander.
- To vanish by dispersion.
- To cause energy to be lost through its conversion to heat.
- To be dissolute in conduct.