Harddisk utilizatin after upgrading from 9.x to 10.x

Can I boot back into 9.x ?

if it is 10.1.x or later, i understand hard drive is re-formatted (i.e. 9.x partition is already gone).

Is my previous 9.x still taking up my HD space and how to swap it completely and how to check it?

have you tried "switchbool -l", "bigpipe software" or "tmsh show sys software"?

What is the size of the new volume created by 10.x?

is lvscan useful?

sol10817: Determining the disk-formatting scheme used by a BIG-IP version 10.x system

Can I specify the size of the volume while creating one? What should be the min. or max size of the Volume that is created?

i do not think it is possible to specify the size.