Ours will be 10 months in a matter of a couple days, and neither of them crawl. They were born 6 weeks early, so their adjusted age is only 8.5 months. At the 9 month check, their pedi was not worried. I'm not really worried about it, just surprised, because they're both so smart, and have hit all their other milestones on time, even though they're preemies.
Some people say that some babies just don't crawl until RIGHT before they walk. My coworkers grandson started crawling at 12 months and walked a week later...so who knows. Thoughts?