Firstly you should know that your female dog is free from any disease because she is 9 years old and usually dogs are not used for breeding at this age but pregnancy is possible at this age. Secondly, 4 months old puppy is not adult. He can not make her pregnant. Even immediately after puberty, male dogs have poor quality of sperms and pregnancy can be difficult. Ideal age for him to make a dog pregnant is 2 years.