I'm eager to change outside space for animal collection (9)
I believe the answer is:
menagerie
'animal collection' is the definition.
(I've seen this before)
'i'm eager to change outside space' is the wordplay.
'to change' indicates anagramming the letters.
'outside' means one lot of letters goes inside another.
'space' becomes 'en' (in printing, a space as wide as a letter 'n').
'im'+'eager'='imeager'
'imeager' is an anagram of 'magerie'.
'magerie' placed around 'en' is 'MENAGERIE'.
'for' is the link.
(Other definitions for menagerie that I've seen before include "Animals go in here" , "Wild animal collection" , "Exhibited collection of wild animals" , "Zoo" , "Assembly of animals" .)