Put the boot into some footballers for illicit payments (9)
I believe the answer is:
kickbacks
'payments' is the definition.
(kickback is a kind of payment)
'put the boot into some footballers for illicit' is the wordplay.
I cannot really see how this works, but
'boot' could be 'kick' (synonyms) and 'kick' is located in the answer.
'some' could be 'a' and 'a' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for kickbacks that I've seen before include "Payments for favours" , "Bribes" .)