I looked at finishers in the local 8K turkey trot for a typical year (pre-Covid). So, as a starting point, these are age 60+ guys who are motivated to enter a running event, and were able to complete it.
Total male finishers age 60-99: 668
Male finishers age 60-99 who ran sub-9:00 mile pace: 86
Percent under 9:00 pace: 12.9%
Stats for just the M60-64 group: Of 330 finishers, there were 48 under 9-min-pace (14.5%)