I'm not sure either of your choices is the ideal compliance match for a JMW-9. (I know if you ask VPI about a Shelter they'll tell you it's a great match. If you ask them tomorrow about a Grado they'll tell you the same thing. Apparently they think they're created the world's first universal tonearm. Caveat emptor.)
I'd suggest something with higher compliance than a Shelter but lower than a Grado. Jsujo's Dynavector suggestion is one possibility. A ZYX RS30 is another. If you're hankering after that Grado warmth, a Benz might suit your tastes without risking Grado's two known faults, exceptional susceptability to humming from EMI and early suspension breakdown leading to the ever popular "Grado dance", a/k/a "Grado wobble".
I'd suggest something with higher compliance than a Shelter but lower than a Grado. Jsujo's Dynavector suggestion is one possibility. A ZYX RS30 is another. If you're hankering after that Grado warmth, a Benz might suit your tastes without risking Grado's two known faults, exceptional susceptability to humming from EMI and early suspension breakdown leading to the ever popular "Grado dance", a/k/a "Grado wobble".