Hello, I have an 8 week Rottie weights 9.5 lbs... I don't know but I see him small for his short age... is this weight at this stage normal?

Puppies can grow at different rates. The runt can have the possibility to become the biggest pup out of the litter.

Don't micro manager your pup. He'll grow. He may not grow up to be the 100+lb rottie, but I'm sure he will get some size to him.

Where the parents big? That's usually a good sign he is going to be big.

Also, with large breeds such as rotties, who have hip issues, you don't ever want your pup to grow to fast. Get him on a good quality large breed puppy food. I recommend Innova Large Breed Puppy. It's a good, holistic food with no fillers or questionable sources.
http://www.innovapet.com/product_line.asp?id=1259

If you have any other questions and concerns about your pup, contact your breeder. They will know a lot about their own dogs and will be able to tell you a for sure answer on whether this little guy is too small.