Gandalf on Tom Bombadil

[Mumriken]

'No, I should not put it so,' said Gandalf. 'Say rather that the Ring has no power over him. He is his own master. But he cannot alter the Ring itself, nor break its power over others.'

Would a vala be able to break it's will over others? I don't think one should take what the elves says too seriously. They are after all just children in comparison to Gandalf. But then Gandalf says he is his own master, which once again suggests he is no maia. Because all maias were under some of the valas. So would any vala be able to break the power of the ring?