Most likely not, unless the St. Kilda City Council was really demanding and refused to take no for an answer, or other options were unavailable to the league. In 1908, I could not see the League interested in expansions to the south instead of the the east as with Richmond. North Melbourne would have been even less probable with Port in the League, and that makes me on second thought think St. Kilda would have tried, but Port and South would have certainly united to stop such a bid.St Kilda is the interesting one - would they have been included in the 1908 or 1925 expansions? Or would they be what Port Melbourne is now?
In 1925 when Footscray were desiring admission, as with both Port and South in the League, Footscray would have had no hope of gaining Port’s putative metropolitan zone. However, South’s would have likely covered all of the City of St. Kilda, and so St. Kilda would have been equally unacceptable to them. We might have seen a one-club expansion to the southeast (Hawthorn or Prahran or even Brighton) instead of the actual three-club expansion for this reason but the fact that those were three of the poorest VFA clubs means even such a one-club expansion would have created major problems in the long term.
As for St. Kilda remaining in the VFA, I am unsure as to how they would have done after it split from the VFL. The Saints would have been much less likely to get the business and industrial patronage needed to be even a VFA power than Footscray, North, Port or even Brunswick, for reasons I have constantly discussed for many years. They would have certainly found it easier with so much competition removed, so there is the possibility St. Kilda would have been far more successful in the Association than they were in the League, but not so successful as Port became I feel.