The most common and most likely answer to this crossword clue is the 9 letter word PLAYROOMS
I've seen this crossword clue in The Guardian
P
L
A
Y
R
O
O
M
S
Buddy explains!
The straight part
We know that "Children’s workspaces? Just the opposite" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case children’s workspaces? just the opposite = playrooms.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 PLAYROOMS mean?
PLAYROOMS noun- A room, allocated as a children's play area, in which noisy or boisterous activities are tolerated.
- (BDSM) A room dedicated to sadomasochistic sexual activity.