The most common and most likely answer to this crossword clue is the 9 letter word REDOUNDED
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More clues leading to the result REDOUNDED
Buddy explains!

The straight part
We know that "boomed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case boomed = redounded.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 REDOUNDED mean?
REDOUNDED verb- To swell up (of water, waves etc.); to overflow, to surge (of bodily fluids).
- To contribute to an advantage or disadvantage for someone or something.
- To contribute to the honour, shame etc. of a person or organisation.
- To reverberate, to echo.
- To reflect (honour, shame etc.) to or onto someone.
- To attach, come back, accrue to someone; to reflect back on or upon someone (of honour, shame etc.).
- To arise from or out of something.
- (of a wave, flood, etc.) To roll back; to be sent or driven back.