I think £9 p/h isn't much above minimum wage, and a qualified cutter is worth more. At all levels this is a hazardous, and very demanding job.
FWIW I pay (on self-employed basis).
£10 per hour - Unskilled groundsman (no tickets bar first aid, just manual labour - not even allowed to fuel saws). I provide safety gear and restrict what they can do. My main groundie has never had a running saw in his hand. After 8 hours on site they go to a flat fee of £100. I expect very hard work from them.
£15 per hour - qualified on the ground cutter.
£20 per hour - qualified climber.
I use another qualified climber and two groundsmen - but I do have to mix and match carefully to protect my profit on a job.
I expect everyone to do their job and the jobs below them as well. e.g. If I'm up the tree then the other climber is dragging brash out with the groundie or feeding the chipper. No work to rule here. Everyone pitches in.
If it's predominately a ground cutting job, or there's only a small fee, then I might negotiate the climber down to £15 per hour. It's up to him if he wants it.
For the qualified guys I provide fuel but I expect them to have their own saws and kit. (Doesn't stop them using my saws when my back's turned, but hey!).
If it's a short job and some travelling involved by the guys using their own transport I may give them an added payment to help out with that.
I hear tales of qualified people working for £75 a day, or being kept as an 'apprentice' for years to keep their salary down.
I don't think it's right.
People work harder and smarter, and they are more committed to you and your business if they can see that you value what they do and reward them at a level which demonstrates that. But I expect a level of effort in return which reflects their appreciation of the fact. It goes both ways.
One more thing - the guys I bring in know exactly how much a job is worth, and how much we are making from it on an individual basis - including my own profit.
I mainly do residential work, which can pay quite well.
Don't know if this is of much use to you.