A current hot topic in correlated electron physics is the magnetic phase diagram resulting from competing Kondo and RKKY interactions with magnetic frustration. One interesting system in this context may be CeNi9Ga4 and solid solutions CeNi9Ge4-xGax which crystallize in a tetragonal structure. CeNi9Ge4 was found to be near a heavy fermion quantum critical point, showing a paramagnetic ground state with a huge Sommerfeld coefficient, exceeding 5.5 J/molK² . The latter appears being stabilized by its quasi-quartet crystal field (CEF) ground state degeneracy. In the solid solution series CeNi9Ge4-xGax we observe a pronounced weakening of the Kondo interaction and the appearance of long range magnetic order with a maximum TN ~2.8 K for CeNi9Ge3Ga. We proposed here to investigate crystal field excitations in this system in order to understand the complex magnetic ground state.