Moons coinciding with months possible?

[Devor]

Much beyond that, if you're writing fantasy the reader isn't going to need the details (and in many cases won't want them), so I wouldn't say a whole lot more unless you come across another glaring issue where the moons would have an impact.

This. I think, honestly, this is one of those times where a vaguer answer makes sense. Astronomy is a complicated science, and really answering the question involves mathematical abstractions, even if it can somehow be made to work. This is literally the sort of question for which calculus was invented, and saying too much about it is going to highlight any mistakes you might be making in putting your system together. Unless there's some reason the exact model of your solar system is needed, I would just hang a lampshade on it and move on.

 

[Fnord]

Actually mapping this all out will take a lot of advanced math relating to orbits, axial tilt, the speed of rotation, etc to see if it's feasible; a lot more work than most readers would certainly bother with. If George R.R. Martin can make a world where summers and winters can last a decade without having to explain how things like crop management can actually occur (just ask any horticulturist what the consequences of no regular winterization would do), or the fact that Krynn from the Dragonlance books can have three moons without extreme tidal effects (since the moons are often portrayed as being in the sky overhead often simultaneously and thus on the same side of the planet at the same time), you're probably safe with the "one planet a month in the sky".

I understand your desire for physical consistency (I'm a stickler myself), but you're probably going to be the only one who really cares in the end.

 

[Devor]

Okay, I think I figured out how it could work.

There are situations in the universe where two stars orbit each other. If Earth is orbiting one star, and the nine planets are orbitting the other star, I think you should be able to make it work. The two orbits would have to be perpendicular to each other, so that Earth would always have a clear view of the second star and whatever planet is "up next" in the order. Since the planets are moving closer to, then further from, the earth, you could even avoid having two visible at once.

Of course, now you'd also have a giant star in the sky.

 

[Steerpike]

Maybe the second "star" is a small black hole with enough pull to have planets orbiting it, but not enough to suck everything in for a few million years. Then you won't have a blazing star in the sky.