i have big anouncement to make !
it was not working through a fw external partition where i wanted to restore/put the .iso boot image ... convinced that the .iso s were corrupt,
but thanks to stewc , i just burned the iso to CD with toast , before i had CHRP boot error with cd in OF,
\\ tbxi cd: or something, did not work, giving the annoying chrp error, but i found a short-cut
multi-boot cd !!! and it booted smoothly for the first time (no disk with question mark) and went way along the mac os 9 boot route ... without manually blessing the system folder & system file(Mac OS ROM) in the system folder ...
So yeah after 5 days of sweating & crying & desperately staying up late, red eyes & what not
Mac OS 9 officially, i can announce, works with PPC G4 Aluminium Powerbook 15 inch ! 1Ghz
Hurray Hurray Hurray !

So tbh the booting of the first iso was the most complex for me
1) finding the right ISO
2) burn to CD
3) OF tricks ending in multi-boot cd
4) from then on just follow the instructions that automatically pop on yr screen
i.e. a) diskdrive mac os 9 app (by that time you are already in mac os 9 (restore) CD disk)
to partition your mac os 9 drive (it's called initialize in mac os 9 lingo )
b) restore through , i forgot the name of the app, image/software restore or something
the .img that is on the mac os 9 CD ...
F7 to go to the right screen ( 2 options for monitor)
5) very important: erase multiprocessing folder (also in trash recyclebin)
install jasper graphic driver (from darth vader)
erase or move all ati & nvidia acceleration & other graphical drivers
to the extensions-off or other map
If you don't do this , it can freeze
if it freezes, just press apple + shift + ESC to put acceleration OFF
++
https://mac-classic.com/articles/mac-os-9-on-unsupported-systems/i actually followed this, except for the multi-boot fw line after device-end
So yeah, now it boots from an exernal fw hdd partition, that probably i can just put in the internal atapi
or pata connector inside the powerbook ... next step will be probably finding a ssd sata to ide adapter