Port, variety going into barrels at intervals (9)
I believe the answer is:
archangel
'port' is the definition.
(city and port in Archangelsk oblast, Russia)
'variety going into barrels at intervals' is the wordplay.
'variety' becomes 'change' (synonyms).
'going into' is an insertion indicator.
'at intervals' means one should take alternating letters (letters are taken at regular intervals).
The alternating letters of 'barrels' are 'arl'.
'change' placed inside 'arl' is 'ARCHANGEL'.
(Other definitions for archangel that I've seen before include "Divine messenger - Russian port" , "Raphael, perhaps" , "What we call a port" , "celestial flier" , "Nag Rachel (anag.)" .)