Instrument is erected outside, as arranged (9)
I believe the answer is:
organised
'arranged' is the definition.
(organising is a kind of arranging)
'instrument is erected outside' is the wordplay.
'instrument' becomes 'organ' (organ is a kind of instrument).
'is erected' becomes 'is constructed' ('be constructed' can be a synonym of 'be erected').
'outside' says to hollow out the word (remove centre letters).
'isconstructed' with its middle taken out is 'ised'.
'organ'+'ised'='ORGANISED'
'as' is the link.
(Other definitions for organised that I've seen before include "Put in order" , "Set up, mobilised" , "Efficient" , "Methodical" , "fixed up" .)