Couple possessed of such wild happiness initially will require this conveyance (9)
I believe the answer is:
pushchair
'this conveyance' is the definition.
(pushchair is a kind of conveyance)
'couple possessed of such wild happiness initially' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'such' is 'ushc' which is located in the answer.
This explanation may well be incorrect...
'will require' is the link.
Can you help me to learn more?
(Other definitions for pushchair that I've seen before include "Baby mover" , "Baby transport" , "transport for youngster" .)