You could make full user backups of 1.9 courses and attempt restore to your 3.9.x, but users will not come across. If you have used plugin/addons in the 1.9 ... restore to 3.9 some of those plugins may or may not come across/work (make sure if you have addons, the same addons are installed in the 3.9.x before attempting course restores).
So the bottom line is ... no and yes - depending upon unkown factors.
Think in 1.9 you could export users information and then import users into 3.9.x via csv. But that won't put them into courses.
Good luck!
'SoS', Ken