Child development 6–9 months

You and your baby are starting to feel (and act) like separate people. Your baby is starting to sit up, move by rolling, reach out, and act on the world. They worry that you might not come back when you go away and will let you know it. Your baby will respond to you giving them lots of things to look at, touch, play with and safely put in their mouth.

Time playing on their tummy on the floor will strengthen baby’s back and help them learn to crawl.

Physical Development
Your baby will put everything in their mouth. Your baby’s lips and tongue are the most sensitive part of their body and will give them lots of information about texture, shape and taste. Also, you can swallow some bits of the world (such as food) but not others, and they are just learning this.

Safety is very important.

Your baby will start to take some mashed solids around this time, and later some soft finger food, such as toast (under your supervision).
At first it is hard for baby to work out the eating action because they are used to sucking, so keeping the food inside the mouth can be hard.
Just because the mashed pumpkin gets spat out does not necessarily mean they don’t like it, they just may not yet have got the hang of keeping it inside their mouth and coordinating when to swallow. Different textures feel very strange to them at first.
Moving
At some time during these 4 months your baby will be able to:

roll over, front to back and back to front
sit alone for a few moments when you put them into a sitting position, then manage to sit by themself without falling over
do push ups when on their tummy – lift their head and chest off the floor and support themself on outstretched arms
start to move while on their tummy, first ‘commando’ style, pulling themself along on their arms, then crawl on all fours
reach for a rattle and shake it
swap a toy from one hand to the other
find their feet, play with them and put them in their mouth.

https://www.healthywa.wa.gov.au/Articles/A_E/Child-development-6-9-months