Magical Training from PGtF lets you cast some 0-level spells as a sorcerer (or wizard, but the heck with that; we've got enough feats to take Extra Spell for everything in existence). With Feat Focus, Practiced Spellcaster sets your CL to your HD. With Versatile Spellcaster + Sanctum Spell + Heighten Spell, you could burn the two cantrips/day from Magical Training to cast a prestidigitation or what have you Heightened to 1st level and counting as 2nd (in your sanctum). Now you take Extra Slot a couple of times, gaining two extra level 1 spell slots (since the highest you could cast is 2). Now you could burn those to cast a Heightened (to 2nd level) prestidigitation which counts as a 3rd-level spell in your sanctum, et cetera. Repeat until 9ths. Use Extra Spell to learn anything you want (while in your sanctum, you can cast 10th-level spells and so can nab 9ths with Extra Spell).