To spread my wings, I had turned to write poetry (9)
I believe the answer is:
diversify
'to spread my wings' is the definition.
(to spread one's wings is to diversify)
'i had turned to write poetry' is the wordplay.
'i had' becomes 'i'd' (contraction).
'turned' shows that the letters should be reversed in order.
'to write poetry' becomes 'versify' (I've seen this before).
'id' written backwards gives 'di'.
'di'+'versify'='DIVERSIFY'
(Other definitions for diversify that I've seen before include "To do something different" , "Become more varied" .)