A few possibilities to consider (I read your post, not other comments):
1. They have too many things or too free access to crafting materials. Remove those items from their room, get rid of things, or require them to come to you to get craft materials (and return those craft materials to you before checking out another bin of a different craft material).
2. I have kids who need specific jobs and your 5 year old sounds like she could benefit. So when it is time to clean the bedroom assign one child to pick up all stuffed animals (or toys or a specific kind of toy) and the other child to pick up all clothing (or paper or books.. you get the idea). Once they finish that task they get a new assignment (great job! now go pick up all ______). This will make it so that the oldest isn’t left to do all the work. Just know beforehand what jobs there are and give the oldest just part of them, saving the rest for the 5 year old no matter how long she takes. A HUGE part of this being successful will be my first suggestion – getting rid of stuff and having a limit on how many craft things they get out at once.
Do I think sharing a room can be good? Yes. It can also be bad if you let the younger (or any one child) get out of all the work. Yes, we want to teach our kids to serve others, but it sounds like your 5 year old is making the 9 year old her slave and won’t learn to do basic chores, much less serve others, because she’s not being required to.
Mine share rooms, they simply have to. currently we have 5 kids in one bedroom and 3 kids in another, with a baby due in a few months. For the bedtime issues – it is always a work in progress, isn’t it? We have strict rules about bedtime for sanity. When bedtime arrives everyone gets in their bed and stays in it. They may have a book light (limits the brightness in the room for those who may be ready to sleep right away). They may have a book or coloring materials. We turn on an audio book for 30-60 minutes depending on the day. When the audio book is turned off their book lights go off as well. They may now lay in their bed.
3. This will be my most controversial suggestion, bear with me to the end. I’ll be honest, ‘night owl’ is a habit, as is going to bed at an earlier time. Yes, each person has a natural time they tend to wake or sleep WHEN THEY ARE BORN. You are not stuck with it, what you choose to do day to day affects it – media/screen time, lights on, and other things will impact this. Yes, if you stay up with lights on until 11pm watching tv, playing with favorite toys, or reading a great book night after night your body will adjust and naturally begin to stay awake until 11pm each night (and sleep later in the morning in an effort to get enough sleep). The opposite is true. If you begin waking at 7am (or 6 or 5) every morning and getting lights on, moving around, and beginning your day your body will naturally begin to wake at that time. The conflict comes when you try to live both at once – keep the late night lights and activities while switching to the early mornings. You force your body to choose and generally it’s going to keep waking later in the morning trying to get enough sleep from being kept up the night before. Which is a vicious cycle that means you won’t be tired come an earlier bedtime (say 8:30pm) and so you stay up again with lights and activities and it repeats.
All of that to say that you need to get both kids sharing a room on the same schedule. Either both become night owls or both learn to be early birds (and go to be earlier at the same time). (Ok, there is a 3rd option, get the night owl to stay out of the bedroom until they are ready to sleep, so that the earlier sleeper can get to sleep when their body is ready. I know some people choose this but it eliminates having all the kids in bed so parents have some alone time. Up to you!). Am I going to tell you that the ‘right’ answer is to get your oldest switched to an earlier bedtime? Nope. Each family is different. At my house we have ended up with a middle ground bedtime (or what I think of as middle ground). Lights go dim to booklights at 8:30pm and out by 9:30pm. So 9:30 to me is middle of the early or late to bed time frame. Everyone is up by 7am at the latest (most wake naturally between 6am-7am). We have a wide range of ages (14-2) and this works for us. My sister lives in another state, homeschools her 4 kids, and they go with night owl for everyone. They don’t dim lights or head near bedrooms until 11pm, and nobody gets up before 9 or 10am. It works for them. Find what works for your family, but obviously having two kids sharing a room on totally different sleep schedules is causing problems, so consider which sleep schedule to shift everyone towards.
