The sub-milliKelvin sensitivity achieved in the Q-band (31-50GHz) line survey of IRC+10216 obtained with the Yebes 40m telescope reveals the presence of several new vibrational HC_9_N overtones (nu_19_>=2) beyond the already reported nu_19_=1. The newly found series of rotational lines appears in seven groups with rotational constants (B) between 291.252 and 293.465MHz, with integer quantum numbers from J_up_=54 to 81 and upper-level excitation energies up to ~600K, well above what is typical of lines found in the outer part of this circumstellar envelope. All evidence, especially the spectral splitting of the l-doubling components and the spacing between B values, unambiguously points toward rotational lines within nu_19_=2-8 that appear surprisingly strong, possibly due to very efficient infrared pumping and slow decay via the nu_19_ mode. The detection of nu_19_=5, 6, 7, and 8 has been possible thanks to collapsed l-doubling components to a single or only two spectral features per rotational transition. To obtain a correct determination of the abundance of HC_9_N in IRC+10216 one has to take into account that about ~70% is estimated to be in the vibrationally excited nu_19_ states.