Some geek full of energy played with ... (9)
I believe the answer is:
partnered
'played with' is the definition.
The definition and answer can be both to do with social activities as well as being past participle verbs.
Perhaps you can see a link between them that I can't see?
'some geek full of energy' is the wordplay.
'some' becomes 'part' (**).
'geek' becomes 'nerd' (I've seen this before).
'full of' means one lot of letters goes inside another.
'energy' becomes 'e' (physics symbol as in E=mca).
'nerd' enclosing 'e' is 'nered'.
'part'+'nered'='PARTNERED'
Can you help me to learn more?
(Another definition for partnered that I've seen is " support".)