Carts on JMW 9 Signature

No problem, I'm not pushing the Blackbird, but if you search, you will find a lot of Blackbird owners also are Scout owners, so it does work on a VPI table/arm.
As will many of the Dynavectors and Lyras that are also very popular with VPI tables.
Try to avoid cartridges under 7 grams in weight and with a compliance lower than 10 and you should be good to go.

Have fun picking one out.

I have already had some bad luck, thank you for the input.

What 'bad luck' have you had? Have you had trouble setting a cartridge up on this arm? What kind of issues are you having?

I have tried a Grado Sonata and Shelter 501 on my 9 sig, while 95% of the time they both sounded incredible, I could never get rid of IGD and mistracking at high amplitude/frequency peaks. I used a Mint and OCD'ed on alignment and tracking force to no avail. So, VPI agrees that these carts are not compatible with the 9" arms due to less mass, but are fine with the 10" arms. I would just like to find something that "works".

Well the Grado weighs less than 7 grams, and the Shelter has a compliance lower than 10, so yes, you could expect some problems with these cartridges.
That's why the rule of thumb with VPI tonearms is weight of 7 grams or more and compliance of 10 or more.