I think you are mistaking "meteor blast", for meteor MASH, or Draco meteor. Arceus can't learn meteor mash, but can learn Draco meteor by leveling it while it's holding the Draco plate.
arceus can learn judgement at level 100
Arceus learn Judgment on level...100
Level 100. Judgement's type depends on which plate Arceus is holding.
Level 55
on level 53
level 100
Blaziken does not learn fire blast. But a TM could.
Arceus learns Judgment at Level 100 in Pokémon Platinum.
level 40
it comes with that move
It can learn it through tutoring by iris
It can learn it at level 50 or by TM.