Training some smart little monkeys (9)
I believe the answer is:
marmosets
'little monkeys' is the definition.
'marmosets' can be an answer for 'monkeys' (marmoset is a kind of monkey). I'm not certain of the 'little' bit.
'training some smart' is the wordplay.
'training' indicates an anagram (to train can mean to grow something into a shape).
'some'+'smart'='somesmart'
'somesmart' is an anagram of 'MARMOSETS'.
Can you help me to learn more?
(Other definitions for marmosets that I've seen before include "Monkeys with silky coats and long tails" , "The monkeys could give Moms a rest" .)