The popular Vanguard ETFs will definitely have it, they do track CRSP and FTSE Russell (VT and VTI for example) - Both of which adopted fast track rules that will allow SpaceX to become eligible 5 days after the IPO. Unless Vanguard themselves decide not to include it in their portfolios (seems unlikely but you never know). I think Vanguard does have some funds specific to tracking S&P but that's not usually what people use Vanguard for.
e.g.
https://moneywise.com/news/top-stories/elon-musk-spacex-ipo-crsp-vti-ftse-russell-nasdaq-401k
That could lead to some interesting outcomes, how these funds look in 12 months could indeed be tied to which specific index(s) they are tracking.