If you take Beguiler 2, Wizard 3, UM10, Archmage 1-5 you should get 9th level Wiz spells with Practiced Spellcaster (Beguiler) taken at 3rd.
Should be CL 11 with both classes when you get to UM7, so you can choose to give the increase to the Wizard casting, that gets you 9th level spells.