have you had it checked? It shouldn't be really bothering him at 8 months and my friends little miss had a hernia that they only discovered when she was still unhappy on her tummy at 8 months.

Chase crawled at 4 months 3 weeks and Ashton is about to start but he loves his tummy time. Jaidan bum shuffled everywhere until 11 months. Every bub is different but if he is really unhappy on his tummy that would be worrying me, not the fact that he isn't crawling.