JI can and routinely do reach the octave with 1-3, 1-4, or 1-5, and 2-4 and 2-5. Useful for fingering alternatives!
Female, about 50, played for about 5 years in adulthood. My reach has not changed at all despite endless of exercises on and away from the piano. It is what it is and I have to modify the music. I can play an octave rather well on the left, but not comfortably on the right. Because my joints are hypermobile I can strech with my fingertips for a 9th on the very edge of the keys, but due to my hand structure it's not much use in actual playing.
Which only goes to show that one can play beautifully without having huge hands!