The most common and most likely answer to this crossword clue is the 9 letter word CERTIFIED
I've seen this crossword clue in The Times
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Buddy explains!

The straight part
We know that "Quality-assured/bananas" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case quality-assured/bananas = certified.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 CERTIFIED mean?
CERTIFIED verb- To attest to (a fact) as the truth.
- To authenticate or verify in writing.
- To attest that a product, service, organization, or person has met an official standard.
- To inform; to tell (a person) that something is true.
- To assure (oneself) of something; to ascertain.