The most common and most likely answer to this crossword clue is the 9 letter word RESPONDER
I've seen this crossword clue in The Guardian
R
E
S
P
O
N
D
E
R
Buddy explains!
The straight part
We know that "I have an answer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case i have an answer = responder.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 RESPONDER mean?
RESPONDER noun- One who responds.
- A person who responds to an emergency situation or other summons.