I'm having the similar issues on Mojave with VMWare Fusion 8.5.9. It was working just fine for at least a week after I installed Mojave, and I've been running VMs with no problem until today. It appeared to start after I rebooted my machine for the first time since my initial Mojave install. It's not showing up as being blocked under Security & Privacy, and vmmon definitely doesn't exist under /dev. This isn't happening on an install, it just... stopped working. I've tried reinstalling, to no avail.
dev1 at MacBook-Pro in ~
$ kextstat | grep vmware
183 1 0xffffff7f84caa000 0x11000 0x11000 com.vmware.kext.vmci (90.8.1) F7FEC1A0-6065-3C60-82FA-CD514D144D16 <12 5 4 3 1>
184 0 0xffffff7f84cbb000 0x15000 0x15000 com.vmware.kext.vmnet (0752.74.38) 8D3E716A-99B9-3729-BFFD-8F799079DB18 <183 5 4 3 1>
dev1 at MacBook-Pro in ~
$ sudo kextutil /Applications/VMware\ Fusion.app/Contents/Library/kexts/vmmon.kext
(kernel) Kext com.vmware.kext.vmx86 start failed (result 0x5).
(kernel) Kext com.vmware.kext.vmx86 failed to load (0xdc008017).
(kernel) Failed to load kext com.vmware.kext.vmx86 (error 0xdc008017).
Failed to load /Library/StagedExtensions/Applications/VMware Fusion.app/Contents/Library/kexts/vmmon.kext - (libkern/kext) kext (kmod) start/stop routine failed.