so is it possible to get one in S/M? or do i have to wait for

You buy the virtual console version of either Red, Blue or Yellow, and supposedly you will be able to transfer Pokémon you catch there into Sun and Moon at some point in the future.

No way to get non-Alolan forms ATM. The Tree can still use them though.

wait for the pokebank to come out?

In order to regular evolve the Alolan forms, you have to level them up in Kanto when you're inevitably granted access there in Pokemon Stars.

>>31244117
I don't even think that will work. The little D-pad symbol next to the marks on the summary page indicates that they're from Alola, so they will probably still evolve into an Alolan Marowak. Likewise, if a Cubone is transferred from a non-Alona game it will evolve into a regular Marowak.

>>31244148
It doesn't. If in Alola it evolves into Alola, except if bred with a regular one. Cubone, Pikachu and Exeggcute are the only ones where it applies because all the other Alola forms have separate Pokemon for every single member.