The most common and most likely answer to this crossword clue is the 9 letter word BALLS-UPS
I've seen this crossword clue in Financial Times
B
A
L
L
S
-
U
P
S
More clues leading to the result BALLS-UPS
Buddy explains!
The straight part
We know that "big blunders" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case big blunders = balls-ups.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 BALLS-UPS mean?
BALLS-UPS noun- Something which becomes muddled or botched in some way.