(if you don't enter the nano world) the single-crystal compliances depend on the material only. So the single grain shows the same properties no matter if it is in a bulk, film or powder. The macroscopic properties depends on the microstructure (i.e. the assembly of those single crystals). Expect therefore different response from a random or a textured polycrystal or from specimen with different grain shapes.
So you acn use them provided you consider the microstructure in calculating the Young modulus (a film might easily be macroscopically transversely isotropic)