Question: Can you make progress on squats when training them every 9-10 days?
Answer: Yes. Of course the question is, "Can you make MORE progress if you squat more often?" For some, yes. For others, no. But it is generally at the expense of something else. In training, like life, nothing is free. You always have to pay a price. For many people, when they increase squatting frequency, their deadlifts and bench presses will suffer. And then this becomes an issue - so training is always a balancing act with a lot of variables with a lot of right and wrong answers. And these answers will change throughout your training career. In other words, what works when you are 20 years old doesn't always work 10 years later.
If your mind has been compromised by the current "Squat Volume" propaganda you can simply add in some lighter squats as a warm-up prior to your DL training. You could also add in DB squats (or some single leg variations) as part of your assistance protocol.
Remember that belief is very, very powerful. And if you embark on a program without 100% faith, it is going to tank. I've seen way too many people who have "less the desirable" training (according to the Volume Addicts) due to work, family and other commitments kick a ton of ass by simply being smart, being insanely consistent and giving tremendous effort. I've seen many methods/programs work for this very reason.
But if you feel you need it, add it in. I don't think it will hurt one bit. It's important to also note that these questions come up when lifters feel that what they're doing isn't the most perfect program. There are only ever going to be relatively tiny windows in your life (if any) where your training can come first or can even be in the top three. You have to continue to train when things can't be perfect or even close to perfect.