'fraid you missed a few there, Tom. Ribald has most ninth level spells for sale in his secret stash (Adventurers mart). He also has a few eighth. You find a few more ninth in the various rooms and battles in Suldanesselar. There aren't many places you can but either. Even eighth level are mostly found. You just have to look in the places that are available in the later stages of the game.
PS. I've mentioned it before and I'll ask again: Does anyone know a sure place to get Spell Trigger? I never found one in my game.