Kentish Town station's entrance surveyed by female eagles (9)
I believe the answer is:
sheerness
'kentish town' is the definition.
(town in Kent)
'station's entrance surveyed by female eagles' is the wordplay.
'entrance' indicates taking the first letters.
'surveyed by' is a charade indicator (letters next to each other) (some letters survey or overlook those beneath them).
'female' becomes 'she' ('she' refers to a woman).
'eagles' becomes 'ernes' (erne is a kind of eagle).
The first letter of 'stations' is 's'.
'she'+'ernes'='sheernes'
's' put after 'sheernes' is 'SHEERNESS'.
(Other definitions for sheerness that I've seen before include "Kent resort" , "Kentish Town" , "Perpendicularity; Isle of Sheppey town" , "Site of former naval dockyard in Isle of Sheppey" , "Feature of cliff" .)