Did Luke really create Kylo Ren?

Until they give us some more exposition on that moment, we'll never know.

Did Luke do what he did because Kylo attacked a young student? Killed a young student? If he did maybe Kylo was already on his way to what we have. Was Snoke tinkering with Luke's mood? Was Snoke manipulating and distorting Luke's perception? Then maybe Luke's actions did, but it could be debatable if he's really at fault.

We know Snoke was involved in Ben's corruption. How much of that gets the blame? We don't know what Snoke did to corrupt Ben, so we can't really know how far gone Ben was. We don't know how Ben processed the abuse, or if he was even aware of it. We don't know if Ben was inclined to go that way before Snoke's involvement, or if there was a time before Snoke was involved. We don't know if Luke was aware at a time when he could have done something about it.

There are simply too many unanswered questions to answer your question with any confidence, because the absence of that information could be manipulated to something that can completely destroy anyone's guess. I think after IX we can make better guesses at this. Right now, we haven't been given enough of that story to make a definite answer or even venture a guess. We can't make an educated guess, because there's a void of information around the whole incident.

 

In Star Wars, as usually with real life, one person is rarely at fault for how another person turns out.
Luke was wrong yes, he admits as much, but Ben still didn't have to turn. It is ultimately the fault of Ben Solo for accepting the darkness.
Snoke manipulated him and set things in motion but it's still Ben's decision and as influenced as it is, he should be held responsible for it.
Anakin was mislead by Palpatine but it was all still Anakin's decisions that made him into Vader. He was just seeking approval for things he wanted to do already. Much like how Ben felt he was owed or deserved things....

 

Whilst I definitely agree, the fact is both Leia and Luke cited Snoke for corrupting Ben and turning him to the dark side. The only reason we attach any blame to Snoke is because we're told by them that he was involved. But if Luke and Leia weren't aware of Snoke's influence at the time, how did they know enough to blame him afterwards? That puzzles me. How much of the picture are they aware of compared to us regarding Snoke's involvement?

There's nothing on-screen to show us that Snoke did anything, so I guess we'll just have wait to find out (if ever) how and why they came to that conclusion. Right now, I have a hard time seeing how he could've been that much involved, certainly not in the case of how Sidious got involved anyway. Rather than a couple of flashbacks or lines of exposition, this story will require proper fleshing out like Anakin's was.

 

Luke didn't create Kylo Ren, he merely lit the match over the bonfire. At the point in which Luke confronted Ben, it seemed that he was already heavily corrupted by Snoke, so I think his turning was inevitable. Luke only quickened the process, and finally pushed Ben over the edge a little earlier than he perhaps otherwise would have.

 

The flashback scenes imply that he had a lot of darkness in him allready, and seeing all the pain and suffering it would cause, Luke wanted to end it before it happened. Thereby he scared Ben, which must have pushed him even further toward the dark. So he had a part in it IMO, but he is not solely responsible for creating Kylo Ren.

This a reflection of what happened with Anakin (which Luke refers to when he mentions Vader being trained by a Jedi). I also think it mirrors how Anakin turned to the dark side because of how he wanted to stop Padme from dying and because of that he caused her death.