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Long-range order of electric quadrupole moments is one characteristic phenomenon in the family of multipolar Kondo systems. The heavy-fermion metal YbRu₂Ge₂ enters a ferro-quadrupolar (FQ) phase below T_FQ=10K, in which the B_1g-symmetry quadrupole moments at Yb³⁺ sites order at zero wave vector [Proc. Natl. Acad. Sci. U.S.A. 116, 7232 (2019)]. This FQ phase is a realization of electronic nematic states since the electronic properties spontaneously break the four-fold rotational symmetry of the tetragonal crystal. We study the quadrupolar fluctuations of this compound by Raman scattering [Phys. Rev. B 99, 235104 (2019)]. The electronic Raman susceptibility in quadrupolar symmetry channels exhibit nearly Curie-law behavior, indicating weak exchange interactions between local quadrupoles. It is the relatively strong coupling between the quadrupole moments and the lattice strain fields in the B_1g symmetry channel, analogous to cooperative Jahn-Teller effect, that enhances the vanishingly small Weiss temperature to the temperature of quadrupolar phase transition at T_FQ.