there are a few classic 9" tone arm verses 12" tone arm points to consider. this is assuming all other things are equal between the 2 arms.
1--a 9" arm will have less mechanical resonance. just by being shorter.
2--a 9" arm will be less set-up critical. if you make the same degree of error in geometry with a 9" arm it will have less audible consequence. put another way, more care is needed setting up a 12" arm, more precision.
3--if you do nail the 12" arm set-up then you do get better performance overall, simply because the wider arc has less overall distortion than the shorter arm. less the issue of lower mechanical solidity. the 12" arm likely has more soundstage size and scale.
so there are trade-offs. if you are a beginner learning set-up i would tend to recommend the shorter arm to begin with. but if you are the type to work at it, after a few go arounds of set-up the 12" will have a higher ceiling to reach.
i’m not commenting specifically about these particular arms, just the advantages of each length generally.
as you move up the ladder of tone arm quality, the length is down the list of factors in terms of performance significance. but at the modest end it matters more where there are compromises in the build. you look for advantages where you can find them to compliment your needs.