So sorry to hear this it is horrible not knowing what is happening.
Yes, I had a very similar experience.
My hcg rose very, very slowly, went up to a max of almost 200 and at 'eight weeks' they gave me an injection of methotrexate to dissolve whatever was wherever it was.
With your very low levels, and rising so very slowy and in terms of not being able to see anything at nine weeks, they will, I'm sure, have informed you that the pregnancy is not viable.
I suspect the 'see what happens' is about seeing whether you miscarry or whether you need intervention like I did.
They suspected mine was ectopic, but we didn't find out.
I'm so sorry to hear that this is also happening to you.
I began to bleed at five weeks, and then stopped after three days. I then bled again twenty days later, which lasted for five weeks, and required methotrexate about half way through the bleeding. I needed antibiotics at the end, to stop the bleeding.