The most common and most likely answer to this crossword clue is the 9 letter word BALLOONED
I've seen this crossword clue in Independent
B
A
L
L
O
O
N
E
D
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 BALLOONED mean?
BALLOONED verb- To increase or expand rapidly.
- To go up or voyage in a balloon.
- To take up in, or as if in, a balloon.
- To inflate like a balloon.
- To strike (a ball) so that it flies high in the air.