The most common and most likely answer to this crossword clue is the 6 plus 5 letter word OFFICE HOURS
I've seen this crossword clue in Financial Times
O
F
F
I
C
E
H
O
U
R
S
More clues leading to the result OFFICE HOURS
Buddy explains!
The straight part
We know that "9 to 5, traditionally" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case 9 to 5, traditionally = office hours.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.