Experimental shelter Senora Peron set up (9)
I believe the answer is:
tentative
'experimental' is the definition.
(tentative can mean experimental or exploratory)
'shelter senora peron set up' is the wordplay.
'shelter' becomes 'tent' (canvas shelter).
'senora peron' becomes 'evita' (I've seen this in another clue).
'set up' shows that the letters should be reversed in order (in a down clue, letters go up).
'evita' reversed gives 'ative'.
'tent'+'ative'='TENTATIVE'
(Other definitions for tentative that I've seen before include "Cautious - provisional" , "Hesitant; provisional" , "Experimental" , "Exploratory, unconfident" , "Exploratory - hesitant" .)