Is this a modern kitchen or more traditional, I usually run cabinets right to the ceiling why waste space and I would certainly do that is your space as your ceiling is already lower than usual so why draw attention to the fact with mouldings.

Cabinets "to the ceiling" is usually a misnomer, as most ceilings aren't flat enough to do that with, and with full overlay doors, you run the risk of rubbing the ceiling when operating a door. I always use a molding of some type to disguise that inevitable out of level ceiling. Depending on the aesthetic, it can be a multi pieced stacked crown, or it can be a plain filler scribed to the ceiling contour. Are 33" cabinets not offered by your cabinet line? That would be an option, with a filler piece or small crown, depending on your style.

Sorry I agree you need a filler but I almost always do modern kitchens so that is very minimal in my design. But I still think smaller and non descript in this kitchen would be best as the ceiling is so low.

Have you thought about going to a 20" backsplash height instead to take up the extra inches?