As long as outlets are on a 15-amp circuit. You can use 14/2 wire for outlets. 14/2 wire will not be enough if the outlets are on a 20-amp circuit. On 20-amp circuits, you’ll need to upgrade to 12/2 wire for all outlets.
A supply duct should not be used for cable runs. Plenum-rated cables are meant for commercial facilities where the region above the drop ceiling is only used as a return air and can run via return ducts.