Figure drip in gallery is experimental (9)
I believe the answer is:
tentative
'experimental' is the definition.
(tentative can mean experimental or exploratory)
'figure drip in gallery' is the wordplay.
'figure' becomes 'ten' (ten is a number).
'drip' becomes 'IV' (intravenous drip).
'in' means one lot of letters goes inside another.
'gallery' becomes 'tate' (Tate Modern, Tate Britain etc).
'iv' inserted inside 'tate' is 'tative'.
'ten'+'tative'='TENTATIVE'
'is' acts as a link.
(Other definitions for tentative that I've seen before include "Exploratory - hesitant" , "Not sure" , "Hesitant; not certain" , "Diffident" , "To be confirmed" .)