It took me much more time (~3 years) than the author here. I meditated following a book. And the what is described here as J7/J8 happened while meditating. But, J9 happened where I didn't expect it. My dad learned yoga from a guru, and he taught me some Pranayama to ease my breathing, as I have chronic cold often. That works, but I experienced J9 (here) while doing those Pranayama rather than Sati meditation. I didn't expect it or was "trying" anything, but it happened there.

The author sheds no light in their state of learning or lifestyle. If I had to venture a guess, I would think that they play significant role..

Following Buddhist eight fold path as much as you can, serving the needy, leading a mindful life, and knowing the basics of mythology, philosophy, etc. probably will help.