The most common and most likely answer to this crossword clue is the 6 plus 3 letter word SPORTS CAR
I've seen this crossword clue in Financial Times
S
P
O
R
T
S
C
A
R
More clues leading to the result SPORTS CAR
- Fast vehicle left on board motoring organisation sent back
- Wear short muffler, one that goes with a zip
- Proudly display evidence of accident, in fast vehicle
- . Automobile association having tantrums looking over vehicle
- Zippy little number to bear evidence of damage
- One’s quick to display mark
- Contest evidence of accident in fast vehicle
- Mark underwear found in high performance vehicle
- Fast runner to show off brand
- Racer left mark after skidding at the start
Buddy explains!

The straight part
We know that "One’s quick" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one’s quick = sports car.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.