This has been a project of mine for awhile, a mobile emulation station that I always have with me. The note 9 can pretty easily emulate every console up to and including the Wii, with the exception of the PS2/PS3/XBox as those emulators are either non-existant or generally bad for Android.
Using a USB-C dongle or USB-C to HDMI cord, you can hook it up to a TV, and use wired or wireless controllers with no problem, at 1080p. With 128GB base storage, and an SD Card slot...plenty of room for games.
Using a bluetooth controller like the Gamesir T1S which hold the phone makes this a hand held system:
Still configuring some parts of this, but it's been working pretty darn well.
For emulators, been playing with Retroarch, which is a horribly designed but wonderfully flexible app, which can support almost every emulator you would want. The exception being the Gamecube and Wii, for which we'll need Dolphin.
Then I used ARC Browser as a way to navigate all the games.
This video is pretty close to what I'm aiming to achive, I'm mostly there save for some filter effects: