I recently played the Android version of Galimulator, and it turns out that playing as Neutrals there doesn't actually work all that well - you'll constantly receive war declarations from pre-existing Empires...and the same empire can keep repeatedly sending you wardecs. Since the game pauses every time a wardec occurs, the game itself slows to an unplayable crawl. Since playing as Neutrals is an easter egg, and thus not actually officially supported, it's advisable to switch to playing a 'real' Empire instead. The Android version* has new features such as religions, factions, diplomacy, and the ability to choose your next leader when your current leader kicks the bucket...so it's certainly worth trying out.
Meanwhile, back on the iOS version, weirdly, when I reached TL9, the button to reform my government wasn't greyed out, so I was able to clear out my corruption and prolong my rule (though it means losing the Transcendence state). Eventually though degeneration sent me back down to TL7, but I'm still able to hold mostly half the galaxy under the Neutrals' thumbs even in that weakened state (likely because empires are used to wiping out the Neutrals back when they're at a lowly TL1). It would be nice to know what decides whether government reform is 'enabled' or not for Transcending empires, but in practice, it's probably wouldn't impact the endgame of the Neutrals.
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*And most likely the PC version as well...though I have never actually played that, since it cost money to get.
EDIT: Just got a message from Snoddasman, the programmer behind Galimulator, that states that in the next Android update, war declarations are hidden when you're playing Neutrals...so that should deal with the slowdown problem. It's advisable to play a 'real' Empire though, since the Android version is more complex (and thus may not support Neutral-play as effectively as iOS does). Specifically, Android has features (factions, diplomacy) that are dependent on what type of leader you have...and Neutrals don't have leaders, thereby leading to undefined behavior.