Squatting for you means she accepts your dominance. That's unusual for a broody hen, they normally don't accept any dominance, so I'd suspect it probably means she is getting ready to wean her chicks. They sure don't squat for my roosters. That may or may not mean she is getting ready to lay. Each hen is an individual.
A lot of the squatting and mating behavior is more about dominance than egg laying. I've seen a 13 week old pullet willingly squat for a 13 week old cockerel and it was over two months before she started to lay. Squatting is often tied to a certain level of maturity which often relates to the onset of egg laying, but not always. It's a sign that it might be about to happen, not that it is absolutely ready to happen.
Before a hen starts to lay she builds up excess fat. This excess fat is what she mostly lives on while sitting in the nest incubating the eggs. That's why she doesn't have to get up much to eat and drink while incubating. Different hens have to store up different amounts of fat before they start laying. Some recover after incubating a lot faster than others. Some eat and drink a lot more while incubating or raising their chicks so they recover faster.
I've had broody hens wean their chicks at three weeks a few times. I've had some go past 9 weeks. I've had some stop caring for the chicks at night but taking care of them during the day. I've had hens leave the chicks alone during the day but sleep with them at night. Typically mine care for theirs until 5 to 8 weeks but there can sure be exceptions. I let my broody hens decide that.
I had a hen start laying 2-1/2 weeks after her chicks hatched, she was one of those that weaned them at three weeks. I thought a predator had taken the hen when I saw the chicks running around all confused but no, she was on a nest laying an egg. She was my only green egg layer at the time so I knew she was actually laying. Most of mine wait a few weeks after they wean their chicks to start laying again but each hen is an individual. As far as I know that's the only one that started laying before she weaned her chicks but most of mine don't have that distinctive an egg. it may have happened and I didn't notice.
Broody behavior and egg laying both rely on hormones to a certain extent, especially broodies. Those hormones are stronger in some hens than others and some hens react to those hormones differently. Most hens will have typical reactions to those hormones but every now and then you get a hen that really gets mixed up.
I've had the same hens hatch and raise chicks more than once. They are not always consistent from one time going through that process to another. And no, my hens don't always do a better job the second time they raised chicks than the first. I see a lot of warnings on here about how badly a first time broody might do. That's not been my experience. Each time is unique. Most of my broody hens do a great job, first time or not.
At nine weeks it's highly likely your hen is getting ready to wean her chicks, even if she went 4 months the first time she was broody. She may be getting ready to resume laying, some of that will depend on how well she has been eating while raising those chicks so she could store up nutrients. But I can't tell you for sure, chickens are so inconsistent and a lot of this is on instinct, let alone the differences in how hormones hit them.
