Tomes assembled in top house (9)
I believe the answer is:
homestead
'house' is the definition.
(I have seen 'House of station' mean 'homestead' so perhaps 'house' could also mean 'homestead')
'tomes assembled in top' is the wordplay.
'assembled' is an anagram indicator.
'in' is an insertion indicator.
'top' becomes 'head' (synonyms).
'tomes' is an anagram of 'omest'.
'omest' inserted into 'head' is 'HOMESTEAD'.
(Other definitions for homestead that I've seen before include "Dwelling" , "House of station" , "US ranch house" , "House with adjoining farm" .)