It gives potter one after table ends secured (8)
I believe the answer is:
tethered
'secured' is the definition.
'it gives potter one after table ends' is the wordplay.
'it gives potter one' becomes 'thered' (the red ball is worth one point in snooker).
'after' is a charade indicator (letters next to each other).
'ends' suggests removing the centre.
'table' with its centre taken out is 'te'.
'thered' after 'te' is 'TETHERED'.
(Other definitions for tethered that I've seen before include "Restrained with a rope" , "on a leash" , "Tied to something with a rope" , "Confined in range by tied rope" , "Bound" .)