So the unwanted options happened to be set by some grub conf.
I override it with the following in /etc/default/grub:
GRUB_CMDLINE_LINUX_DEFAULT="... nouveau.modeset=1"
Then I updated the initramfs img with dracut -f and it's fixed !
$ cat /sys/module/nouveau/parameters/modeset $ 1
The driver begins to write to the device ! Now I'll have to fix a permission issue on /dev/dri/card1 ...