It should sprout some roots eventually, at which point you can remove it with a very sharp cutting tool (those plant fibres are very tough in Vandas). If you try to remove it now it may sprout roots but probably without losing a few leaves first...Maybe more than a few...
If it doesn't have roots, definitely do not remove it.
Even if it does have roots, I don't recommend dividing. I've had repeated problems with this practice. I tried it again recently and I failed again. I tried removing keikis by twisting them off instead of cutting them. I absolutely refuse to make divisions of my Vandas because of the experiences I've had. I just let them grow into a bush.
I had the same question few years back,talking to the vendor where I got the vandas suggested to wait until top section has developed good solid roots then just slice off the mother plant which in turn will leave some hefty root system for all the keikis to flourish. Haven't done it yet but this spring I really have to do something about the, as they are now become more of a headache with their size.