We show theoretically that polariton pairs with a high degree of polarization entanglement can be produced through parametric scattering. In our proposed scheme, varying the polarizations of the two pumps, we have a complete control over the symmetries of the produced state (i.e. singlet or triplet output). Our microscopic model shows how a tomographic reconstruction, based on two-time correlation functions, can provide a quantitative assessment of the level of entanglement produced under realistic experimental conditions. Our study provides a suggestive perspective towards hybrid all-optical quantum devices where quantum information can be efficiently generated and controlled within the same structure. This result puts forward the robustness of pair correlations in solid-state devices, even when noise dominates one-body correlations.