There are a lot of barred & cuckoo varieties out there. Scot's Grey, cuckoo Dorkings, barred Hollands, to name a few. If you're sure that there are no Marans where you live, it could be a different cross, but I am pretty sure that if one parent was a Legbar then the other parent is barred or...
He is young, definitely under a year old. 9 months is a good estimate.
I think he is probably an olive egger, cream Legbar crossed with cuckoo Marans. He has the little head tassle of Legbars, and also the white earlobes, plus the white legs of a Marans.