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

The straight part
We know that "performing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case performing = executant.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 EXECUTANT mean?
EXECUTANT noun- A person who executes a dance or piece of music; a performer.
- A person who puts something into action, such as a plan or design.