Kylo has never met Snoke in person. Killing Han was the final test to prove his devotion before Snoke would believe he had turned from the Light.

As soon as he and Hux get there, Kylo destroys Snoke, takes Hux (+Phasma) hostage, and returns to the Resistance.

+When he's praying to Vader he's asking his redeemed grandfather for guidance and so he can "Finish what you started...when you killed the Emperor."
++Leia had no idea about what he was doing.