Odin's powers are both magic and cosmic related.
Odin took down Surtur.
Odin has proven to be more powerful than Thanos.
Odin is super-humanly intelligent and wise.
Odin is a sky-Father. Sky-Fathers are powerful on a cosmic scale.
Odin has a goddamn eight-legged horse, two smart ravens and two immortal wolves.
Gender: Unspecified Location: Speedblitzing around the universe f
A lot of Sentry's feats are hearsay. when he stalemated Galactus, we heard it from Spiderman. We didn't see it so we didn't know how hungry he was or what exactly "stalemate" means. If Spiderman saw Thor drive away G, he wouldn' have said, "using an Odin-enhanced Godblast, he beat up G!", he would have just said Thor whooped G. And we all know Thor isn't more powerful than G. The reader is robbed of context.
So Sentry's power may range from around Thor level, in which case Odin destroys him to Galactus level, in which case he beats Odin. If I had a guess I would put him in the former category and give the win to Odin.
Gotta be Odin he's cosmic level. He's design to be above your common hero that may appear in a strip. Odin will never have his own regular strip cos he is so powerful it would be dull to read.
I think it would depend on where they are fighting. If they fought in Asgard, Odin would have home-feild advantage.....but since the city is made of shiny gold and rainbows...that gives Sentry a lot of photons to power him to unimaginable limits.