You officially have nine shopping days left until Christmas, but a few St. Louis luminaries dropped off some seasonal treats a little early this year. Yesterday both Cave States and a one-off duet by Beth Bombara and Seth Porter were posted online, and both take an adult view of the Christmas season while still seeking joy in a taxing time of year.Porter and Bombara recorded the twangy “Gray Christmas” with Bombara’s husband Kit Hamon on drums and Nashville native Samuel Gregg on guitar.…