If a Japanese person read that, they would say "hoshi no yume no owari ni," 'hoshi' meaning, essentially, blips in the sky, a.k.a. stars, or distant planets.
But, I see your point. Having it be the "Planet's" dream would certainly make more sense in the context of the game. And yes, that kanji "SEI" is applied to the suffix of elemental kanji (water, ocean, heaven, earth, gold, fire) to make the names of the planets. So, I have no problem making it the "Planet's dream," although when you talk about a "planet" in japanese, you say "waku-sei" (two kanji). I think we should check Robo's conversation about the "Entity/Planet" for final confirmation.
