I don't think they're armed by the nine. I don't remember seeing anything like that. They seem to merely have a somewhat tumultuous relationship (since they did something to upset the nine during a recon mission, they gave them skolas as a gift, then the nine had xur release skolas with his own ketch to go start over). The Awoken don't seem to have an affiliation with either the light or dark, as most of their tech seems to be derived from old golden aged ships. Additionally, there's another piece of lore that indicates ghosts are susceptible to damage. Invective's text states, "They made a grab for my ghost. After that, it was a short conversation." Indicating that Ikora (the owner of invective) was having a conversation/argument with a normal person and the person tried to grab/harm her ghost. Considering these bits, the lack of any lore supporting the theory that ghosts are invincible aside from darkness absorbing their light, and the multitude of dead ghosts, I'm going to stick with the general theory that ghost's physical shell can be damaged and destroyed.