My LO sits unaided beautifully. Will only roll in her crib when no one is "watching" (we see her on the monitor). Won't roll or crawl in her playpen. Barely stands with assistance. I'll discuss it at her development review but I'm not overly worried just want to discuss it. My LO is nearly 10m as well :)
My son didn’t roll till he was 9 months and didn’t do anything else either but he didn’t seem floppy/weak so I wasn’t worried. Walked just after he turned 1 but I’m pretty sure he’s hyper mobile so that might explain him being slightly late getting started compared to his big sister (who may also be be hyper mobile but now where near as rubbery)