The most common and most likely answer to this crossword clue is the 9 letter word FACTIONAL
I've seen this crossword clue in The Daily Telegraph
F
A
C
T
I
O
N
A
L
More clues leading to the result FACTIONAL
Buddy explains!

The straight part
We know that "liable to be disruptive" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case liable to be disruptive = factional.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 FACTIONAL mean?
FACTIONAL adjective- Of, pertaining to, or composed of factions.