What to get after nine assembly toys for young one? (6)
I believe the answer is:
kitten
'what to get after nine assembly toys' is the definition.
I can't tell whether this defines the answer.
'young one?' is the wordplay.
'young' becomes 'kit' (kit is a kind of young).
'one?' becomes 'ten' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'kit'+'ten'='KITTEN'
'for' is the link.
Can you help me to learn more?
(Other definitions for kitten that I've seen before include "Baby rabbit" , "Young feline animal" , "Little Tom, perhaps" , "Baby cat" , "Young of a beaver" .)