The most common and most likely answer to this crossword clue is the 9 letter word FRONT-END
F
R
O
N
T
-
E
N
D
Buddy explains!

The straight part
We know that "it involves interaction with the public" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it involves interaction with the public = front-end.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 FRONT-END mean?
FRONT-END noun- That part of a hardware or software system that is conceptually closest to the user; the user interface.
- Relating to the front end or user interface of a hardware or software system.
- Of a financial transaction, paid or charged first.