The most common and most likely answer to this crossword clue is the 9 letter word SHRIEKING
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Buddy explains!

The straight part
We know that "letting out a cry" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case letting out a cry = shrieking.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 SHRIEKING mean?
SHRIEKING verb- To utter a loud, sharp, shrill sound or cry, as do some birds and beasts; to scream, as in a sudden fright, in horror or anguish.
- To utter sharply and shrilly; to utter in or with a shriek or shrieks.
- A sound that shrieks.