The most common and most likely answer to this crossword clue is the 9 letter word LOITERING
I've seen this crossword clue in The Times
L
O
I
T
E
R
I
N
G
Buddy explains!

The straight part
We know that "hanging around for client?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hanging around for client? = loitering.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 LOITERING mean?
LOITERING verb- To stand about without any aim or purpose; to stand about idly.
- To remain at a certain place instead of moving on.
- For an aircraft to remain in the air near a target.
- The action of the verb loiter.