Accountant with vivacity allowed in carriage (9)
I believe the answer is:
cabriolet
'carriage' is the definition.
(cabriolet is a kind of carriage)
'accountant with vivacity allowed' is the wordplay.
'accountant' becomes 'ca' (abbreviation for chartered accountant).
'with' says to put letters next to each other.
'vivacity' becomes 'brio' (I've seen this before).
'allowed' becomes 'let' (I've seen this before).
'ca'+'brio'+'let'='CABRIOLET'
'in' acts as a link.
(Other definitions for cabriolet that I've seen before include "Soft-top car" , "Light two-wheeled carriage" , "Horse-drawn carriage with two seats and a folding hood" , "Car with a folding roof" , "vehicle" .)