Hi- the galls on the leaf underside were made by grape phylloxera, small aphid-like insects that feed on roots and leaves. It's considered a minor problem and no sprays are necessary. Remove and crush/discard badly infested leaves to reduce the population.
We pge on grape pest problems, including phylloxera- https://extension.umd.edu/hgic/topics/grape-insects

Our entomologist identifed the catepillar as grapevive epimenis (Psychomorpha epimenis). It feeds on grapevines but is not considered a pest insect. Very cool-looking!
Jon