Heighten + Earth Spell can get a spell being the equivalent of a 10th level spell for all level-dependant purposes except it takes a 9th level slot. Using Silent Image and Shadowcraft Mage, you can replicate any Sorcerer/Wizard Evocation, Conjration (Summoning), and Conjuration (Creation) spell up to 9th level, but you only have the casting time and components of Silent Image. Using Arcane Disciple (Luck), you get Miracle added to your class spell list (assuming at least a 19 Wis, but that's easy to get). Since it's an Evocation and now on the Sorcerer/Wizard spell list (assuming you are a Sorcerer or Wizard), it's a fair target to mimic with Silent Image. Since you aren't actually casting Miracle, you don't care about its components (such as the XP cost).
Arcane disciple adds it to the CLASS SPELL LIST. That is the direct wording of the feat. For that character, they become wizard class spells. And yes, you are correct, there are no 10th level spells. With earth magic, 9th level spells become, effectively, 10th level spells. As for Miracle and wish, the descriptions say of equivilent power. Especially in the case of miracle. It lists mostly defensive uses, however, asking Poseidon to use a tidal wave to wipe out an invading army or evil kingdom would be consistent with the power level mentioned in the spell.
Edit: And yes, a DM is very likely to fiat this into non existence. However, the OP requested respective power levels. This would be at the top end of power levels. Considering the Genesis spell allows for vast time manipulation and is also available at level 20, this is a very roundabout way of getting to the same result.