Interposing hand is so-so for its level (5). You would mainly want to use it on big, bad boss monsters while you pelt them with spells. The problem is that those boss monsters tend to be rather large and can probably push the hand back. Alternatively, if they are spellcasters, they can just fire spells past it. Works best for medium-sized fighter types, but for that I would prefer Hold Monster.
Forceful hand (6) is pretty limited IMO. Bull-rushing can be devastating at the right time, but for a sorcerer its not a very good utility spell.
Grasping hand (7) is decent. Again best used on fighter types. Since it doesn't inflict damage spellcasters can T'port or D. Door out of it w/o problem. If you want to imoblize people, Forcecage is much better, albeit quite expensive per casting.
Clenched fist (8) gives the best bang for the buck. When used against an isolated foe it can be devastating. If you are focusing on evocaton (and which sorcerer doesn't

) it can really be a difficult Fort save to make. Also the to hit bonus scales very nicely with level. When combined with certain high-level spells, like Time Stop, it can be a near insta-kill.
Grasping hand (9) looks good on paper but unfortunately doesn't stack up terribly well against other 9th level spells.