The most common and most likely answer to this crossword clue is the 9 letter word OPPOSITES
I've seen this crossword clue in Financial Times
O
P
P
O
S
I
T
E
S
Buddy explains!
The straight part
We know that "They should attract/young and old, for instance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they should attract/young and old, for instance = opposites.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 OPPOSITES mean?
OPPOSITES noun- Something opposite or contrary to something else.
- An opponent.
- An antonym.
- An additive inverse.