You SHOULD be able to pass a 9mm stone, although it's going to hurt like he11.
The reason she might want you to see a urologist is so that they can give you options on how to rid yourself of the stone. There are a number of different procedures they can do to get rid of it, rather than have you try and pass it naturally (which, without knowing you history, body-type, ureteral structure, etc, I can't say for certain if it's possible for you to pass without aid).
Go and see the urologist, as your doctor suggests. She's just a general physician I'd imagine and doesn't want to overstep her bounds and give you semi-good/bad information, so referring you to a specialist is her way of getting you the best help possible for your situation.
I currently have an 11mm stone in my eft kidney, as well as numerous other, smaller stones, and it's going to take surgical intervention, but it's become so routine for me, I don't even worry about it anymore. Been doing it for 20 years, so it's old hat.
If this is your first time, I can understand your anxiety. Take a deep breath. Calm down. Everything's going to be alright. Go and see a urologist and hear what they have to say.
You'll be fine, trust me.
Take care & good luck.
It is difficult for a 9 mm kidney stone to pass on its own in urine. Kindey stones are of four types: calcium oxalate stones, struvite stones, uric acid stones or cystine stones. Potassium citrate is used for the treatment of stones. I would suggest you to get an evaluation done from a urologist to determine the type of stone. Treatment modes include Extracorporeal Shock Wave Lithrotripsy (ESWL), uteroscopic stone removal and percutaneoud nephrolithotomy.
I hope it helps. Take care and regards.