'The princess of Alderaan has disrupted my plan'

That's what Palpatine tells Pryde. He's talking about Leia's intervention during the Kylo-Rey duel.

If you watch the scene, Kylo was about to kill Rey when that happened. So that was Palpatine's plan. He wanted Kylo to kill Rey. He feared Rey in ways he didn't fear Kylo. Rey represented the jedi threat, while Kylo was more of a puppet to him.

So by implication, his original plan was to possess Kylo's body after the jedi threat, Rey, had been taken care of. He would have liked to avoid confronting Rey, and with good reason.

What we have in the film is Palpatine's plan B.

A bit of inference: since the possession ritual involved pushing the soon-to-be victim to kill the possessor in anger, then in the original plan Palpatine would have made Kylo angry without telling him about the possession ritual. Kylo killed Snoke in cold blood, but that's not how the possession works apparently.

Making Kylo angry, how? It makes one think about his 'she's not who you think she is' at the beginning of the film. At that point, Rey would have been dead - killed by Kylo's own hand.

Leia intervened, and this didn't happen. But maybe we'll get to know about the facts or perspectives this thwarted plan A was built on.