He will end up fighting Eustass Kid. Let me explain.
Before I talk about history/events. I'll address the characters of Luffy and Kidd.
Both Luffy and Kidd have very similiar personalities. Both have a very strong will, a willingness to protect those around them at any cost, a will to fight against impossible odds and both are very stubborn.
Now on to the events/history that will lead to this fight.
Luffy:
From the very first chapter of one piece, we're introduced to Shanks. And you begin to realize Shanks is literally Luffy's savior, mentor and inspiration for his journey. A very important character in Luffy's life. The way he treats Shanks's hat says more than enough. In Luffy's eyes, Shanks is an idol he admires and strives to surpass.
Kidd:
We know Kidd had a very different childhood compared to Luffy. We know at some point, when Kidd was young, the girl he loved was killed because of gang violence. There are theories that Shanks had connections to the underworld. It's very possible he could have been involved with those gangs that caused Victoria's death. This is one possible reason, however, it brings me to my next point. Since we've been introduced Kidd, hes always seemed focused on going after Shanks. Its very clear theres a big reason why Kidd wants to go after Shanks. For now we don't know what that reason may be. This will eventually be revealed. And interestingly Oda has never allowed the two characters to have any direct dialogue. Its abunduntaly clear that Kidd views Shanks very differently in comparison to how luffy does. Kidd views shanks as an enemy, someone who he needs to tear down, while luffy views him as an idol and someone to surpass. I also have suspicions that Shanks has direct connections to the WG, and we know that is something Kidd has no respect for.
Now you might be asking wtf does shanks have to do with a fight between Luffy/Kidd. Shanks will be the catalyst for this fight.
At some point Luffy will learn about the incident that occured with Kidd and Shanks. Either from the giants or at some point on elbaf. At somepoint during elbaf, Kidd will learn about Luffy's relationship with Shanks. This will probably infuriate Kidd. I honestly, would not be surprised if Kidd ends up attacking first.
I am willing to bet, that Kidd/Luffy will fight on elbaf. Kidd is "that guy" that will fight that guy "Luffy."