Dr. Tajunnisa M
Hello. Firstly your 9 week old pup must be chewing due to teething and it's absolutely fine if it has happened while playing. But make your elder one is fully vaccinated. Once your younger one reaches 3 months, he should be fully vaccinated for rabies too. Secondly, if there was no bleeding, you can just wash the wound in running water with soap. If the wound is quite deep with bleeding, your elder one requires a complete post bite vaccination if previous vaccination was not done in 3 months.