Per the revised AR 600-8-19, Enlisted Promotions and Reductions, dated Dec 2016, effective 1 January 2017, SGTs must complete SSD-2 before being boarded for E6, and the Advanced Leader Course for pin-on to SSG. I contacted HRC and was told there are only 12 seats (on average) per class for your MOS. You are number 2 on the list for ALC so you should be attending around January/February 2018.
The Army continues to authorize battlefield promotions for Soldiers in designated areas (combat or under combat conditions) when their commanders determine they have demonstrated an extraordinary performance of duties if they have not completed the Basic Leader Course and or Advanced Leader Course. However, to retain their stripes the Soldiers must complete the BLC or ALC within 270 days after redeployment to home station.