Your bun is over 8 weeks of age, but just barely. Physical
kisses you may want to hold off on for awhile out of an abundance of caution. Young rabbits can still be vulnerable to various pathogens. You can still shower him with
pettings and attention (clean hands) -- at least while he's young enough to not resist
.
Here's an excerpt from
Rabbits: The Mystery of Poop
Without mother's antibodies, complex organic compounds and proper pH environment her milk provides to help protect the baby's intestines, these babies are highly susceptible to over-proliferation of foreign bacteria. One of the most common culprits of runny stool in baby rabbits is accidental infection by the common human intestinal bacterium, Escherichia coli. This is transmitted from humans to baby rabbits during handling, since these bacteria are all over us, not just in our intestines. Handling an unweaned infant rabbit without properly washing and disinfecting one's hands is a good way to transmit these opportunistic pathogens. Even a loving kiss on a too-young baby rabbit's lips can kill. Until a young rabbit is at least eight weeks old, she should not be taken from her mother, as mama's milk affords protection against E. coli and other bacteria until the baby's own immune system can handle them.