My DD has just turned 9 months (yesterday) and had her review with the HV, who is lovely. She told me to start doing things with her such as clapping, reading books, waving hello and goodbye. I then looked on the internet for "games to play with a 9 month old baby" and found all sorts of information about developmental play eg teaching them how to push and pull, respond to questions, point, undo things, recognise objects etc.
My DD is a very happy baby, she loves other people and I talk and play with her during the day eg roll balls back and forth, and she loves physical games such as letting her fall through my legs. But mainly she just loves putting things in her mouth!
But I would be interested to know about other people's babies at this age as she can't do any of the things the HV mentioned like clapping or waving. Also although she can sit up really well she can't crawl yet (although she is a big baby, off the chart in terms of her height and over the 98th percentile for weight).
The guilt that motherhood brings!