The Local and Regional network is run by Go Buses, the Number 21 Northern Connector is bus to look out for. The Busit! site has all the information you should need.
Go to it Here.
The National network is run by Intercity Buses. To find their website go Here.
One of Huntly's quirks includes not having a dedicated Bus Stop in town. The Intercity website states that the bus will stop outside and opposite to the Essex Arms Hotel. The Go Bus will also stop here.