Mona Before I read your whole question I was going to be on the side of 'no, you can't leave your DD', but reading on, I would totally do it.
I also have a 9yo and I leave him for about 10 mins while I pop to the shop. He has also started to go to the park and around the village with his friends (no adult) - telling you this to give you an idea of his maturity.
I love to run, and while I probably could leave him alone for 30 mins, I don't go to the park for laps, but out into the country lanes. I don't feel comfortable doing that yet and know I would not enjoy the run which would be counter productive.
But you are in a single space, not far from home. While you could take her with you and do as themost suggests (which sounds fun) this would not appeal to me as my run time is time AWAY from DS (away from everyone in fact!). It would be fun and get the training in, but not tick the 'head space' box.
I have also done run/cycle with DS which works well.
So, I think what you're suggesting is fine if she is happy to be left alone.