For sure Luffy hates BB a lot because of Ace. I am going with 9 or 10. As said above, they have an interesting and unusual relationship. Like when they met at Jaya, they said the opposite things about the drinks and pies at the bar. However, they both believe in dreams and that the Pirate Era will always live.
The weird thing is how when Blackbeard was saying all these good things about dreams, Luffy was silent and just had a serious/mean look on his face. It was the first time in the anime that Luffy didn't talk to someone after they were basically being nice and encouraging him. So Luffy didn't get along with him from the start and didn't trust BB.
Zoro was quiet as well and that's when this happened in which I hope that someone can please answer this for me: what did Zoro and Luff mean when they said: "it's not he, it's they!" ? about Blackbeard in Jaya. I couldn't have been about BB's crew right cause how did Zoro and Luffy both realize something like that?