1 of 1 people found this helpful
Thank you for your post!
Only the PDF is available through the Developer Subscription. There would be no way for us to transfer or provide a "free" copy (or copy included with your subscription) to your Apple Account.
2 of 2 people found this helpful
As far as I know, there isn't a way to configure or trick iBooks to open a PDF in anything other than Preview. It is just the way it is on macOS.
You'd have to convert the PDF to an ePub file at which point it would / should open natively within iBooks. There are many apps out there, both on the Internet and the Mac App Store, that can assist you in doing this.