Should I ask the school to pick up the pace? What should I hope for?

Ask if they'd allow her to start some GCSE work in the subjects she plans to continue with? She could take a CGP book in. Perhaps this will shame them into a bit of differentiation...

There is often a big jump up when GCSEs kick in.

Maybe we've been spoilt by state school teachers skilled in mixed ability teaching, but good teaching should be accessible across different ability levels. I would be wary of encouraging the idea that it's beneath them. The lessons may not be that interesting but maybe it's just not a great lesson. Of course boring and poorly differentiated lessons exist. But I wouldn't too quickly buy into the idea that it's boring necessarily because it's too easy. This is something that children learn to say because it gives a big ego boost, both to themselves internally and from their parents. And Y9 is a really difficult year developmentally - peak teenager. This will probably squeeze itself out somehow. It may not look like archetype Kevin the Teenager, but it will (should?) still involve some conflict/attitude/moaning even if you think your child is not "that sort" of teen. Also discontentment and disengagement with some subjects is typical in Y9 anyway, as they move towards taking their options.

Rather than talking to school, if they are really keen you could spend time talking with your teen about the subject to inspire them to extend the learning themselves. Alternatively, give light touch sympathy but encourage them to see it as a small part of the day, job done, leaving lots of spare time to do more interesting stuff. Extended learning could involve books or documentaries, debate over the dinner table. There are even online free courses, Khan academy. But personally I would favour the parking it in a small box. Don't feed the drama of how terrible it must be to spend an hour doing something they find easy. Do the equivalent of "if you're bored, tidy your bedroom." They have lots of time ahead to get stuck into GCSE and A Level study, and nothing to stop them starting to self study earlier if they are so minded. But social development is absolutely key at this age and if school is leaving them with plenty of leisure time, good.

That sounds like typical year 9 behaviour.

If she's been prepped for common entrance then some GCSEs are easy by comparison - I don't think my DD did ANY work in French from year 9 to year 11 and she picked up a very easy grade 9 at gcse. Same for Latin although I think she did some work there.

In your shoes I'd start focusing on the longer game - the step up to a level is substantial, Start getting her to think what she might want to focus on - languages, humanities or stem and start looking for the kind of stuff that looks good on uni applications.

Re lessons, mostly questions at this point:

If she was academically challenged in year 8, presumably at a linked prep school, was that mostly from the teachers or were there a group of kids that challenged each other?

If there were a group of kids who challenged each other where did they go? (I have a nasty feeling you are going to say boarding, but still...)

In many senior schools year 9 is not a priority. They have kids to get past A-levels and GCSEs; year 9 is often seen as a settling in year. Your daughter may well find that as she chooses her GCSEs and moves into year 10 the pace picks up a bit - if she chooses for example Latin triple science etc etc then she will mostly be in classes with more motivated students.

However, most teenagers have lazy aspects to their personality and some GCSE classes have not very many people in, so she may have to get used to a medium pace.

I'm in an area where there are a lot of selective indies as well as a few non-selectives and I chose to play the long game as I didn't want my kids totally stressed out by doing 13 GCSEs and being put under massive pressure, which the selectives can be like.

There must be a reason you chose this school. Was it based on the prep head's recommendation? Is it really every subject? You are only about 10 weeks in , so there is time for this to change. Are you sure dc is showing engagement and enthusiasm for the subjects in class? There is nothing to stop them reading ahead, around the subjects etc and you looking for extension opportunities.

If the school is non-selective then there will be a wide spectrum of abilities.

My kids went to a non-selective Indy and some kids failed some GCSEs.

You are paying for them not being at the local school where 15% pass maths and English, believe me they would stand out more there.

If your kid is smart and motivated then the standard response is to expand what they are doing - do they learn an instrument, are they part of the music scene at school, do they do a sport or sports, what other stuff dies the school offer that you can take advantage of? You can start D of E in year 9 once she is 14 and that will really help develop her.

If you want to push forward with the academic subjects then you can look at supercurriculars - if she is into languages can you get some simple books in those languages for her to read, if she is into arts then concerts/exhibitions etc in the local city, if she is into maths then look at 3blue1brown on YouTube etc.