The most common and most likely answer to this crossword clue is the 9 letter word MATTERING
I've seen this crossword clue in The Times
M
A
T
T
E
R
I
N
G
Buddy explains!
The straight part
We know that "making a difference" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case making a difference = mattering.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 MATTERING mean?
MATTERING verb- To be important.
- (in negative constructions) To care about, to mind; to find important.
- To form pus or matter, as an abscess; to maturate.
- The quality of something that matters; significance; importance.