According to Samsung, this subwoofer is only compatible with the Samsung HW-S60T (23W) soundbar. According to my information, the Samsung SWA-W700 (1pc, 25W, Black) would be compatible with your soundbar. Apparently no longer available at Digitec.
This subwoofer is an add-on. Without the Samsung Soundbar HW-S60T or HW-S61T, this unit has no function. For this reason, the Samsung SWA-W500 is not compatible with the Samsung LSP9T projector.