OK for practising on (9)
I believe the answer is:
treatable
'ok' is the definition.
Both the answer and definition are adjectives.
Perhaps there's a link between them I don't understand?
'practising on' is the wordplay.
I cannot really see how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is present in the answer.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for treatable that I've seen before include "one can deal with" , "Can be handled" .)