A number show anger outside church in American port (9)
I believe the answer is:
anchorage
'american port' is the definition.
'a number show anger outside church' is the wordplay.
'number' becomes 'no' (abbreviation for 'number').
'show anger' becomes 'rage'.
'outside' indicates putting letters inside.
'church' becomes 'ch' (common abbreviation).
'no'+'rage'='norage'
'norage' enclosing 'ch' is 'nchorage'.
'a'+'nchorage'='ANCHORAGE'
'in' acts as a link.
(Other definitions for anchorage that I've seen before include "Roads" , "recluse's cell?" , "American city" , "Place where ships may stay safely - in city in Alaska?" , "Roadstead" .)