We make a systematic study of Li isotopes (A = 9, 10, 11) in the tensor optimized shell model for 9 Li and treat the additional valence neutrons in the cluster model approach by taking into account the Pauli-blocking effect caused by the tensor and pairing correlations. We describe the tensor correlations in 9 Li fully in the tensor-optimized shell model, where the variation of the size parameters of the single particle orbits is essential for getting strong tensor correlations. We have shown in our previous study that in 10,11 Li the tensor and pairing correlations in 9 Li are Pauli-blocked by additional valence neutrons, which make the p-shell configurations pushed up in energy. As a result, the s 2 valence neutron component increases to reveal the halo structure of 11 Li and the inversion phenomenon of the single particle spectrum in 10 Li arises. Following the previous study, we demonstrate the reliability of our framework by performing a detailed systematic analysis of the structures of 9,10,11 Li, such as the charge radius, the spatial correlation of halo neutrons of 11 Li and the electromagnetic properties of Li isotopes. The detailed effects of the Pauli-blocking on the spectroscopic properties of 10,11 Li are also discussed. It is found that the blocking acts strongly for the 11 Li ground state rather than for 10 Li and for the dipole excited states of 11 Li, which is mainly caused by the interplay between the tensor correlation in 9 Li and the halo neutrons. The results obtained in these analyses clearly show that the inert core assumption of 9 Li is not realistic to explain the anomalous structures observed in 10,11 Li. For the dipole excitation spectrum of 11 Li, the effect of the final state interactions is discussed in terms of the dipole strength function. * )