Neoteny is easy to achieve in 10k years. Cf. the Soviet experiments on domesticating foxes, which started showing juvenile, gregarious traits in a few generations of selective breeding. In general felids are social in kittenhood within their family unit, most wild species just "grow out of it" in puberty. Selection pressure (natural or artificial) favoring individuals that tolerate or even enjoy human (or conspecifics') presence favors retention of juvenile traits in adulthood, and this change can happen quite quickly.