Hmmm, 9 Hrs driving is nowhere near enough IMO
This is not a race to the finish line of getting your license as fast as possible, you need to become a confident and safe driver on the roads and experience comes with time. One hour instructed driving is better than Four hours non instructed out on the roads making mistakes.
You have appointed this instructor to help you, they will have coached other drivers through to secure their license, my view is that if the instructor thinks 20 hrs driving instruction is required, i would do that and then go out fully secured with all the skill sets and put the practice in with your own car.
The RAC claim that a learner from start to test should have 45 hours of instructed lessons and 20 hours of extra own practice. Not sure i totally agree but remember "you don't know, what you don't know" and as i say the expert is giving you advice for a reason.
Take the advice, take your time, gain the experience and become great safe driver. Good luck