Definitely grapes.
i’m certainly no viticulturist but i think by late summer you’ll know if red or white. and then you might also be able to determine if they are wine or table grapes by the taste and size.
im betting that some people here with experience could rule out a lot and narrow it down to a small list of potential varietals based off all known variables like - region and the leaf type. and even more so as the grapes ripen.
Btw- if this is part of a new home purchase then congrats on the purchase. and enjoy your grapes!