As Anil and Rajesh have said above, 9 months is much too young to breed. Your female should be at the very least 18 months old and your male over 1 year.
Dobermann have quite a few genetic diseases that should be tested for prior to breeding such as vonWillebrands disease (vWD) which is a bleeding disorder. They are also prone to dilated cardiomyopathy and should have annual heart tests to determine if they are in danger of dying from the disease. They should also have their hips tested to make sure they will not suffer from hip dysplasia and pass it on to their pups.
Are both your dogs closely related? You shouldn't breed closely related dogs, especially if they are not health tested.
If you have performed all the health tests necessary for both parents and both have reached the age of reproduction then you may breed them. However, then you must care for the puppies! Puppies can be a lot of work.
Dobermann should have their dewclaws removed and their tail cropped at no more than 4 days old by a vet. You will have to find a vet able to do this BEFORE your dog is pregnant or else you will be stuck with dobermann with their tails and dewclaws. IF you want to sell the puppies with their ears cropped, this must be done at the earliest of 7 weeks old and no later than 12 weeks old. So you must also find a vet who will perform that proceedure.
Someone new to the world of dogs as you are should find a mentor... someone in your area who is already breeding dobermann so you can learn from them.