The most common and most likely answer to this crossword clue is the 9 letter word NEWLYWEDS
I've seen this crossword clue in Financial Times
N
E
W
L
Y
W
E
D
S
More clues leading to the result NEWLYWEDS
Buddy explains!
The straight part
We know that "Happy couple" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case happy couple = newlyweds.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 NEWLYWEDS mean?
NEWLYWEDS noun- A recently married person