Yes, I still use Kirby against t0mmy's ROB. I also use Meta Knight and Dedede. He seems to be at least as good against all three as against my Kirby, but he knows the Kirby match-up really, really, really well.
I would not hesitate to say that ROB has the advantage in the Kirby match-up, though I think it's only slightly. ROB can camp with projectiles or play as aggressively as he likes since he out-prioritizes Kirby like Marth. As bad as it sounds, ROB's inability to KO keeps him from completely owning Kirby (as long as you know what to expect). Kirby on the other hand has his F-smash and Giant Swing, which really help even the odds.
MK and Dedede are likely much better in this match-up, but I haven't had years of practice with them vs. t0mmy like I have with Kirby. Lol.