Limited period for structure after backing issue (9)
I believe the answer is:
timeframe
'limited period' is the definition.
(I've seen this before)
'structure after backing issue' is the wordplay.
'structure' becomes 'frame' (frame is a kind of structure**).
'after' means one lot of letters go next to another.
'backing' says the letters should be written in reverse.
'issue' becomes 'emit' (I've seen this before).
'emit' reversed gives 'time'.
'frame' after 'time' is 'TIMEFRAME'.
'for' is the link.
(Other definitions for timeframe that I've seen before include "Limited period" , "Temporal span" .)