Wife's son, perhaps, lets hip CD play (9)
I believe the answer is:
stepchild
'wife's son' is the definition.
(child by marriage)
'lets hip cd play' is the wordplay.
'play' indicates anagramming the letters.
'lets'+'hip'+'cd'='letshipcd'
'letshipcd' anagrammed gives 'STEPCHILD'.
'perhaps' is the link.
(Other definitions for stepchild that I've seen before include "Spouse's son or daughter from a previous marriage" , "Cinderella, perhaps" , "Somebody else's kid" , "Offspring of spouse" .)