Poets supporting strike-breaker keeping weapons here (9)
I believe the answer is:
scabbards
'keeping weapons here' is the definition.
'poets supporting strike-breaker' is the wordplay.
'poets' becomes 'bards' (bard is a kind of poet).
'supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'strike breaker' becomes 'scab' (I've seen this before).
'bards' after 'scab' is 'SCABBARDS'.
(Other definitions for scabbards that I've seen before include "Blade covers bard's cabs" , "Sheathes for swords, daggers" , "Sheaths for swords or daggers" .)