Excessive woofer movement with a VPI JMW 9 ?

most likely you have the cartridge that is mismatch with the JMW9.
what cartridge are you using?

The problem is not endemic to unipivot arms. The problem is probably an arm/cartridge resonance that is either too low in frequency or too high in amplitude-- or both.

I hesitantly tried the KAB Rumble filter to address the same problem you're having - excessively pumping woofers. I'm glad to report it really did the trick, and with no sonic compromises I can detect. An added, unexpected bonus: my table seems much less susceptible to footfalls with the rumble filter in place than it was without.
Got mine here on A'Gon for around $160 - they turn up every now and then, and you could probably turn it around at no loss if you try it and don't like it.

amp and preamp is?

Yep rumble filter needed....Had a phono amp, cheap variety no rumble filter, bought a little better one with rumble filter, woofers dead solid, dead silent. There is not much below 20hz on a vinyl pressing accept surface noise, so you won't lose anything in the musical sense, just background noise.

Now if you did not have this issue before this arm all together and another one you used originally did not exhibit "this issue" on "this same system" in question than yes it is coming more from the new cart/arm combo, however still can be eliminated using a phono stage with a rumble filter or adding the after market version stated above. Either way you need to block that noise, so starting over with a perfect cart/ arm combo may not be easy, and unnecessary until you try a rumble filter.
Good luck