Single-electron (SC) and double-electron capture (DC) in collisions of metastable Ar8+ ions with H2 have been studied by using X-VUV and Auger spectroscopy at 10 keV per charge. SC by the long-lived metastable ion Ar8+(2p53s)3P0.2 mostly populates inner-shell excited Na-like Ar7+**[(2p53s)3P,nl]2.4Lj levels with n=5, a small fraction going to n=4. With the use of radiative and Auger decay rates, the observed X-VUV and Auger spectra are analyzed and compared with the spectra obtained by other authors. It is shown that the stabilization of these core-excited states is both radiative and autoionizing. DC by the metastable projectile reveals the formation of triply excited Ar6+*** ions. They stabilize along two Auger decay steps: the first one gives a low-energy electron, associated with the decay to the intermediate continua Ar7+(2p53l3l'), while the second step-originating from these Ar7+(2p53l3l') levels-gives a higher-energy electron, characteristic of the decay to the only available continuum Ar8+(2p6)1S0.