What Blondin used in tense Hitchcock film (9)
I believe the answer is:
tightrope
'what blondin used' is the definition.
(Charles Blondin was a tightrope walker)
'tense hitchcock film' is the wordplay.
'tense' becomes 'tight' (similar in meaning).
'hitchcock film' becomes 'rope' (1948 film directed by Alfred Hitchcock).
'tight'+'rope'='TIGHTROPE'
'in' acts as a link.
(Other definitions for tightrope that I've seen before include "An acrobat walks on this high above the ground" , "Entertaining line" , "Difficult thing to walk on" , "High wire" , "On which acrobats walk" .)