^ Interesting point, but I ultimately can't agree in this particular case, because Kylo Ren is just too nothing of a character.
TLJ told us Luke went to have a serious chat with Kylo about his drift to the Dark Side right before everything fell apart, but, apart from Han's line about there being "too much Vader in him," neither
TFA nor
TLJ gave any real hint as to what precipitated said drift in the first place. The answer always was there was never an answer;
TRoS merely acknowledged this by shrugging and saying "It was Palps' long-distance mind contro all along, we guess."
So while it could certainly be interesting to see a character haunted by a Force Ghost, I don't think Kylo in Ep. 9 was the one to be it. And if one wanted to, I guess one could theorize that Force Ghost Luke helped to summon the spirit of Han for Kylo's vision of him in
TRoS, and therefore did "see him around..." from a "certain point of view," of course.