The interesting magnetic phase diagram results 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 tetragonalstructure. 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 CeNi9Ge4-xGax we observed a long range magnetic order with a maximum TN ~2.8 K for CeNi9Ge3Ga, while CeNi9Ga4 shows a weak magnetic transition near 0.5K, which change from FM-type to AFM-type in an applied field >=0.5T. We therefore proposed here to investigate these compounds using musr measurements on HiFi to understand the complex nature of the magnetic ordering.