Cheat
In the Ultima 9 directory there is a file called default.kmp. When opened in a standard wordpad or other text editor you will find the following text line:

[Cheat Commands]

Simply add the following lines underneath it:

alt+shift+i = toggle_avatar_invulnerable
alt+shift+l = toggle_avatar_fly

During game play the corresponding keys (alt+shift+i & alt+shift+l) will activate the cheat functions.

You may also bind the following codes just as you did the ones above:

pass_one_hour
unpass_one_hour
sunrise_sunset
pass_one_minute
unpass_one_minute
toggle_sun
toggle_wind
toggle_storms
toggle_avatar_fast

Extra Cheats
Hey there again, thought you might like an update for the U9 cheats. These are only for patch 1.07 and are employed in the same manner as the ones currently listed.

-New 1.07 Patch Cheat Bindings
Add these to the DEFAULT.KMP file in your U9 folder like so...
"ctrl+r = recharge_mana"

These two are self explanatory.
recharge_mana
fill_spellbook

The following give you spells respectively. You are also given every Sigil, The Orb of the Moons and a Bread. Everything in your backpack is removed when you do these and armor is reverted back to the Avatar's clothing at the beginning of the game.
spells_0-2
spells_3-5
spells_6-8

Hidden teleporters
Locate the fence without a gate behind the Avatar's house. Climb on the nearby training dummy and jump over the fence. Find the level hidden near a bush by the large tree. Pull the lever to find teleporters that will equip your character with armor and allow travel to various places in Britannia. Note: You can not return by teleporter once you leave.

Kill Lord British
At the start of the game go downstairs to the refridgerator. On top of the refridgerator there will be poison. Put the poison into the bread maker. The bread that comes out is poison bread. When you go to Britan give Lord British the bread and soon he will die.