The most common and most likely answer to this crossword clue is the 9 letter word RUMINATES
I've seen this crossword clue in The Guardian
R
U
M
I
N
A
T
E
S
More clues leading to the result RUMINATES
Buddy explains!
The straight part
We know that "Ponders" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ponders = ruminates.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 RUMINATES mean?
RUMINATES verb- To chew cud. (Said of ruminants.) Involves regurgitating partially digested food from the rumen.
- To meditate or reflect.
- To meditate or ponder over; to muse on.