Galactus is BIG. Wolverine can jump several hundreds meters up into the air, and would stab Galactus' pressure points. Humans have pressure points, and Galactus has human-shape, afterall.
Wolverine can jump insanely high, and has proved that in many situations. Like when he fought Spiderman and they were proven even in strenght, and when he dodged Human Torch's flames by jumping 10 meters into the air.
First Galactus is a semi Abstract thus physical attacks will have no effect on him.
Then there is his armor which can take quiet good amount of punishment before it even begin to crack.
Galactus when he was at his most hungry imo, was capable of fending of the Avengers, SS and FF and still with a gesture locked SS with his power Cosmic and stated that he with a gesture could eradicate the Avengers, SS and FF.
Wolverine got a healing factor and is smarter than them. Remember Wolverine disappearing from Nightcrawlers sight? Wolverine could show up everywhere on Galactus' body when he isn't prepared. Wolverine's claws are ADAMANTIUM. Of course, they can cut through his tiny armor. And he is indeed a psychical being, he eats planets. So, Wolverine's pressure pointing works. Wolverine just wins this.
Wolverine will kill Galactus.. come on guys this is spite, Galactus would need the LT to even hope to win this one. You should have made it more fair and took away the Adamantium claws and used bone claw Wolvie, not that it would help much.
Hiding from a being with Cosmic Awarness not likely. No they cannot cut through his "tiny" armor, that armor containes the ability to make a universe inside of it, so tiny not quiet.
He eats planets because his energy is used to keep Abraxas in check, thats why he feeds, and I believe I said Semi Abstract.