Luffy's powers are all about elasticity and rubber-like properties, thanks to the Gomu Gomu no Mi. While he can stretch his body to insane lengths and pack a punch with moves like 'Gomu Gomu no Pistol,' controlling sea waves isn't part of his skill set. The Devil Fruit's limitations are pretty clear—it doesn't grant elemental manipulation like water or fire. If anything, seawater is his biggest weakness, draining his strength on contact. That said, his creativity with his rubber abilities is wild. Imagine him bouncing off waves or using his stretchy limbs to ride them like a surfboard, but outright control? Nah, that's more Poseidon's territory in the 'One Piece' world.
Now, if we're talking about indirect ways, Luffy's Gear Fifth might blur some lines with its toon-like reality bending, but even then, waves aren't his to command. The series keeps water-based powers distinct, usually tied to specific characters or ancient weapons. It's fun to speculate, but Eiichiro Oda's rules are consistent: Luffy punches, stretches, and laughs his way through battles—not conjuring tsunamis. Still, the idea of him ricocheting between waves in a chaotic fight? Pure gold.