That is a very good question, and the answer could be both, and also neither.
Initially, if SNP wins, I would say the movement would be down, mainly because of the uncertainty. Can't say by how much, and whether it would be a temporary reaction.
But an SNP majority doesn't mean they will go straight for a referendum, or that they would win it.
Long term, if Scotland left, the movement could be up, especially if NI looks at following suit. England could be a lean mean Atlantic Singapore. Or not. But this would take some years to eventuate.
I would suggest that people just be aware for now, knowing that there may be volatility, and make plans accordingly.