Yes. It would vacate the 9th Circuit decision and the federal district court's ruling, and would leave the California Supreme Court's ruling (which upheld Prop. 8, albeit only prospectively) in place.
LL says SCOTUS can deny standing to the petitioners two ways: only before SCOTUS or before any federal court.
The former would leave in place the 9th Circuit ruling overtuning Prop. 8 and allowing gay marriage in CA.
The latter would overturn all federal court rulings (including the 9th Curcuit and the federal distric court) and leave in place the CA Supreme Court ruling that upheld Prop. 8 as constitutional.