Glad you got it working mate
Indeed ClassicWB 3.1 versions have LoadModule present and an IF "scsi.device exists on Devs" then Load it.
ClassicWB 3.9 didn't have this feature, cause you could have put it via installing BB3 and BB4 unofficial BoingBags.
By default ClassicWB 3.9 comes with BB2 which means ROM Update and scsi.device 43.43.
You still need to update to a better version of scsi.device to use larger than 4GB hard drive.