Section 9. The director of economic development may establish a regional planning and economic development district consisting of all the cities and towns in the Southeastern Massachusetts Regional Planning District established under this chapter, and the towns of Plymouth, Plympton, Carver and Kingston, to be known as the Southeastern Regional Planning and Economic Development District, provided a determination is made by the United States Secretary of Commerce that said area is eligible for designation as an economic development district in accordance with the provisions of the Public Works and Economic Development Act of 1965.