I have a 9 month old pup that I sent to day care and they taught her to sit. I asked them not to do it but I can't be there all the time and so many people look after her at play time.

How can I stop her from sitting in the ring?
I took her to 1 show already and she kept sitting.

Please help me??

Teach her to Stand. Seriously. If they use "Stay" for a sit, then use a different word for breed ring such as "Pose." If she is confusing the S words, don't use "Stack." That is what the obedience dogs do--Stand for Exam, with handler 6 ft away, off lead.
She is young. Sitting beats rearing and bucking, or shying away.
She will then have two commands down towards her CD, Companion Dog title, and might become a dog with a title at both ends of her name.

I agree, teach her to stand. I teach all of my puppies to sit (and down, stay, come, speak, shake, etc), they can certainly learn more than one thing ;)

When you use the "stand" or "Pose" command, hold the bait lower so she can't sit. Practice, practice.

I agree.

She is super young. Just practice a ton, and make sure you are not using her "day care collar". Dogs are not stupid, you can teach her that when her everyday collar is on, she can sit. But when the show lead goes on, no sitting is allowed.

Practice practice - I agree with Charlotte - put on pup's show collar and teach her to stand: get on your knees with puppy standing in front of you nose to the right. Hold the bait in your right hand in front of pup's nose not too high and say your command in a normal voice. Put your left hand under her belly as you say the command to keep her from sitting. Use lots of praise when she succeeds and practice often keeping your sessions short - always ending on a good note. Once she comes to understand what you are asking of her she will be glad to oblige.

Thanks guys, it does seem to be working.
I practiced all morning :)

If you are up for a little clicker training it can do wonders. Once the clicker is 'loaded' you can teach all kinds of nuances in your dog's behavior-standing included. It's a fun game and there are no wrong response for the dog (or you for that matter). You can 'shape' just about anything from eye contact to barking (or not barking) on command. It's a good tool and fun to boot. Tons of books and classes are available if you are new to the technique.