I never pushed tummy time with my little one...he hated it too. I used to lie to the MCHN when she asked if I was putting him on his tummy at every appointment At around 4 months he learned to roll then was quite happy to be put on his tummy. I just let him do it in his own time and he's perfectly fine, absolutely no issues with development....he was crawling properley at 7 months, standing at 8. My advice would be to go with your instincts on this one. With a 9 week old I don't see any harm in waiting, they are after all still getting used to the big wide world!