I am currently on F1 status in US and have applied for change of status to H4 with I-765 application.
For COS is taking approximately 6-8 months, can I book visa appointment in advance before getting an approval and choose visa appointment date after 6-8 months?
You need an approved petition to book a visa appointment.
Also you dont really newd to do visa stamping unless you plan to travel outside of the US.