So are we to read from this that Trelane is OFFICIALLY a Q? I know that's always been the fan theory, but with John DeLancie voicing his dad, I think that settles it?
Well, it's still somewhat uncertain, but of course using John DeLancie is strong. However, the computer voice on Star Trek is done by Majel Barret, who also played Christine Chapel and Number One, that doesn't mean they are the same person or entity, either.
And if you want to put a twist on it - maybe Trelane is Q, and the Q we hear is his father, and it's still a few million years later. The Q from TNG didn't really seem the type to not mess with humans, after all. And clearly, some effects are different - appearing as the kind of energy cloud, and not using the flashing light for his manipulations are still different from the TNG and Picard era Q.
But if it's a Q, it seems they had a home world once and evolved (or technology advanced) into what they are now.
EDIT:
Damn, I forget to mention something that might be more plausible - Trelane could be Q Junior from VOY, the child of Q and Q. Since Q can time travel, so his age doesn't really tell us much.