yup, you can. You can evolve into Umbreon and Espeon ever since Gen2. That's when they first showed up. Umbreon during the night, Espeon during the day.
Oh and on VBA Emulators, you might get a "battery has run dry" error so time triggered events no longer occur. To fix that, just click on settings and there's a Real Time Clock option under Emulator.
then restart the emulator. the error should poof and those events should trigger again xD