Yes, there is pin trading at Aulani. Although very few Cast Members wear pin lanyards like at DLR and WDW, there are several places around the resort that have pin trading books that guests can look at. The CMs will gladly show you their pin books if you ask. There was a pin trading book at each section of the General Store, another at the Concierge desk, and one at Auntie's Beach House. The only CMs I remember actually wearing a pin lanyard were those at the DVC Preview Center.
Of course, Aulani has several pins for sale that are only available at the resort. If you are into collecting the Disney Worldwide Conservation Fund pins, Aulani has a unique pin that is pink in color.