9,000 is big, although I do think road biking is easier than mountain biking, based on the numbers who fly past me with ease going up hills! ;-)
I went from little to no cycling at the start of Lockdown, to getting it done in May (I’m 46, so hardly a spring chicken). Need to average just shy of 300m a day, which soon builds up if you miss a few days.
I used Strava to plan routes and Challenge Hound to track my progress (and others if you want to rope anyone else in). Easy enough to record. Gets quite addictive once you start.
I’m now doing 4 x 1,000m challenge in June (4 individual rides each over 1km vertical).