Databook never says that Six Paths Senjutsu is a combination of 9 bijuu. It says its a divine state gifted by Hagaromo. He didnt give Naruto the 9 bijuu. He gave him RSM. The powers merged to make the Ultimate RSM with GoudodamaNo I didn't, which is further proof he was using BSM not RSM.
There's no such thing as RSM with Kurama chakra only because Six Path Senjutsu is the combination of the chakra of all 9 bijuu
This is exaclty why I'm saying he wasn't using Six Path Senjutsu, if Naruto and Sasuke used Hagoromo's power there would be no plot for Boruto movie because anyone below JJ Madara is fodder