The most common and most likely answer to this crossword clue is the 9 letter word MIDDLEMAN
I've seen this crossword clue in The Guardian
M
I
D
D
L
E
M
A
N
Buddy explains!
The straight part
We know that "agent/agent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case agent/agent = middleman.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 MIDDLEMAN mean?
MIDDLEMAN noun- An intermediary, agent between two (or more) parties.
- An intermediate dealer between the manufacturer and the retailer or customer.
- One who rents land in large tracts, and lets it in small portions to the peasantry.
- To act as a middleman or intermediary.