Not entirely risky acquiring horse for old coach (9)
I believe the answer is:
charabanc
'old coach' is the definition.
(I've seen this before)
'not entirely risky acquiring horse' is the wordplay.
'not entirely' means to remove the last letter.
'risky' becomes 'chancy' ('chancy' can be a synonym of 'risky').
'acquiring' means one lot of letters goes inside another.
'horse' becomes 'arab' (Arab is an example**).
'chancy' with its final letter taken away is 'chanc'.
'chanc' going around 'arab' is 'CHARABANC'.
'for' acts as a link.
(Other definitions for charabanc that I've seen before include "Old tourist coach" , "Early coach" , "Former coach" , "Old vehicle" , "E.g. transport" .)