Why Android x86 9.0 boots in command line and not in GUI?
According to the answer here from Stack Overflow:


Temporary fix: append nomodeset xforcevesa at the end of the line containing kernel during boot time at the GRUB menu. During boot press E to edit. While on the line containing kernel press E again, append nomodeset xforcevesa at the end, press enter, then press B to boot.
Permanent fix: read the answer here.