There's certainly lots of first home buyers in the market right now, but given the time it takes to find a house and then settle on it, chances are that many landlords wouldn't be hit with vacancies yet even if is is the cause of tenants leaving in the near future.
The good news is that many of these vacancies would start appearing in late January or February, which in many markets is the ideal time to be looking for a new tenant.
Overall though, the tenant pool is quite large and I don't see it having a huge dent on the people looking to rent.