The most common and most likely answer to this crossword clue is the 9 letter word NITPICKED
I've seen this crossword clue in Financial Times
N
I
T
P
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C
K
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More clues leading to the result NITPICKED
Buddy explains!

The straight part
We know that "was overcritical" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case was overcritical = nitpicked.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 NITPICKED mean?
NITPICKED verb- To correct minutiae or find fault in unimportant details.
- To pick nits (lice eggs) from someone’s hair.