Chances are, it’s not the exact Nine that made Xur, and by extension, none of the 9 related to the Emissary and the Starhorse (I’m pretty sure the Starhorse hijacked Xur, and while similar to the 9 isn’t apart of the 9 itself). The exact reason being is that the 9 are split up into two factions, being those that favor humanity and those that don’t. The “good” 9 send us Xur, while the bad 9 have yet to interact with us in any major way outside of keeping the major 9 forces neutral. The Tentacles don’t seem to share any major relationship with Xur other than being related to the 9 (possibly). To any end, they do share some similarities in design philosophy to 9 aesthetic we have seen, albeit shifted to a slight degree. Instead of having the clean cut, shimmery, Awoken+ look of the Emissary and Eternity, it looks more bubbly and liquid like despite being solid. Kind of like resin.