The most common and most likely answer to this crossword clue is the 9 letter word BENEFITED
I've seen this crossword clue in The Times
B
E
N
E
F
I
T
E
D
Buddy explains!
The straight part
We know that "did well" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case did well = benefited.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 BENEFITED mean?
BENEFITED verb- To be or to provide a benefit to.
- To receive a benefit (from); to be a beneficiary.