Everything was fine yesterday but today one branch of my multi-specie Pluot was
all but stripped of leaves (the others had nothing)

Critters are just over an inch with stripes from front to back, over all they
are greenish/grayish.

Plucked them and sprayed with a orange based organic soap.

Hope I got them all, but are they likely to attack my cherry tree? And what
might they be and what's the best way to deal with them

If it helps I'm zone 9 or 10 and the weather is finally changing