Does the gardasil9 vaccine provide little or no protection against hpv 34,35,39,51,56,59,66,68?

There may be some cross protection by the antibodies generated to other strains. However, this has not been fully explored nor would it be expected to provide such protection. Vaccines target the most common strains involved in the issue at hand. When you try to incorporate too many strains in one vaccine the protection against individual strains declines. G9 targets the most common.