Strengthen Religious Education at home, supporting Church (9)
I believe the answer is:
reinforce
'strengthen' is the definition.
(reinforcing is a kind of strengthening)
'religious education at home supporting church' is the wordplay.
'religious education' becomes 're'.
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'supporting' becomes 'for'.
'church' becomes 'ce' (abbreviation for Church of England).
're'+'in'+'for'+'ce'='REINFORCE'
(Other definitions for reinforce that I've seen before include "increase support" , "Strengthen or support with confrerie" , "Buttress" , "provide support" , "Give added strength to" .)