On other systems, SheepShaver provides the first PowerPC G4 emulator, though without MMU, to enable the execution of Mac OS Classic. If you are using a PowerPC-based system, applications will run at native speeds (i.e., without any emulation involved).

Networking: SheepShaver supports Internet and LAN networking via Ethernet and PPP with all Open Transport compatible MacOS applications.

Native QuickDraw 2D acceleration for BitBlt and FillRect operations.

Run-time depth switching from 1 bpp to current host depth settings.

Color video display with support for run-time resolution switching.

File exchange with the host OS via a Unix icon on the Mac desktop.

Copy and paste of text between Mac OS and the host OS.

Basic but portable JIT engine (x86, x86_64, mips).

PowerPC G4 emulation on non-PowerPC platforms, direct execution otherwise.

SheepShaver runs macOS 10.7 through macOS 10.14.

SheepShaver is distributed under the terms of the GNU General Public License (GPL). However, you still need a copy of Mac OS and a PowerMac ROM image to use this program. That is, it enables you to run PowerPC Classic Mac OS software on your computer, even if you are using a different operating system. Anyway, for your Intel Mac, SheepShaver is your only option so be thankful for Gwenole Beauchesne.SheepShaver is an Open Source PowerPC Mac OS run-time environment. It's kinda weird that PPC Macs can run 22 year-old apps while the Intel Macs are limited to 5 years, but that's progress I guess. For whatever reason, Apple decided to kill the Classic mode on Intel-based Macs.

Only problem is a PPC-based Mac is a requirement. However, I would strongly recommend you stick with Apple's Classic mode, as it has much better compatibility, and integrates (almost) seamlessly with OS X. If the System and Applications folders of a non-bootable version of Classic were placed in a disc image and used in a PowerMac emulator, would the image be able to successfully boot OS 9 on the emulator? However, I recall that Mac OS Classic supposedly can be copied entirely to another hard drive by copying the System and Applications folders. Ever since 2003, Apple changed the firmware on their PowerPC machines so that they would no longer be able to boot the included Mac OS 9.2.2 naively.

Mac os 9 sheepshaver