The most common and most likely answer to this crossword clue is the 9 letter word HERODOTUS
I've seen this crossword clue in The Guardian
H
E
R
O
D
O
T
U
S
More clues leading to the result HERODOTUS
- Historian reveals bad king to us in a different way
- Wicked man leading to several books by American historian
- Famous Greek champion to scatter us
- Point grasped by star American historian
- Spot American going after brave man, a famous Greek
- The odours upset a distinguished Greek
- Victor joins party to meet model with American historian
- Period covered by star American historian of old
Buddy explains!

The straight part
We know that "historian" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case historian = herodotus.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.