My ds is 10.5 months and doesn't seem able to crawl. He sits very well unaided, pulls himself forward and rolls onto his back from his front and viva verca.
I sit him on the floor and put a toy in front of him but just out of his reach. He will lean forward to get it, will invariably fall on his front, get up on his arms....and just stay there!
If you support under his arms and hold him up,he puts his feet on the floor and straightens his legs. He is very strong and i'm tending to think he is more lazy than anything else. But...the niggling worry is always at the back of my mind that there is a problem. Am i just being an over anxious first time Mum??