Blurry medium resolution imagery.
Sansha (aka: Woody Island).
In progress work to build this island larger on the north side, piles of sand visible just east of Military Vehicles.
Four launchers in vertical position, four others ready. Each pair of launchers connect by surface cabling to a control vehicle. Radar unit and other vehicles on south side.
Attached news link from February 2016 mentions HQ-9 (S-300 variant).