The most common and most likely answer to this crossword clue is the 9 letter word OFFENDERS
I've seen this crossword clue in The Daily Telegraph
O
F
F
E
N
D
E
R
S
Buddy explains!

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 OFFENDERS mean?
OFFENDERS noun- One who gives or causes offense, or does something wrong.
- A person who commits an offense against the law, a lawbreaker.