Yes, but you’ll have to purchase two tickets as there are no transfers, or you can meet the bus take the bus directly from the mall. The two last stops on the HVIST-6 from Halkali are ArenaPark Mall and the Mall of Istanbul, which will require 30-50 minutes from there to the airport. The HVIST-7 from Beylikduzu comes directly from Marmara Park Shopping Mall and is about 60-70 minutes away. You can also do a ton of street shopping on Iskital Street and then just hop on the HVIST-14 at Taksim Square.