Eh, Odin's never remotely be shown as capable of that, but on top of that, he's also always been shown as arrogant enough to not believe that he would need to. In issue 3, when Galactus tried to control Thor, and to take away all of the power cosmic, Thor said "nope, I'm not like other heralds, I'm not your flunky, you don't take crap away from me, and you sure as shit don't own me, I cooperate with you by choice, and I take from you if I want to." Galactus was pretty thrown back by Thor's response.
Then the scene you mention, in issue 4, when Thor attacks Galactus, clearly hurting him, and forcibly rips away some of (or some more of, or all of) an already amped-up Big G's power cosmic, this is something that clearly shocks and visibly hurts Galactus.
Oh, and it is explained later on, sort of confirming some of the other Old King Thor stuff, that Thor is the one who finally kills Galactus.