Unfortunately no one has made ubuntu packages yet, however here is a script that I built based on Dirk’s post to automate mono 1.9 installation onto Ubuntu environments.

#!/bin/sh

# This is needed to pick up our built mono for commands
export PATH=/usr/local/bin:$PATH 

apt-get install build-essential bison gawk
apt-get install libglib2.0-dev
apt-get install libpng12-dev libx11-dev libfontconfig1-dev
apt-get install libfreetype6-dev libjpeg62-dev libtiff4-dev
apt-get install libungif4-dev libexif-dev libcairo2-dev
apt-get install libpango1.0-dev libgtk2.0-dev libglade2-dev
apt-get install libgnome2-dev libgnomecanvas2-dev libgnomeui-dev
apt-get install libgnomeprint2.2-dev libgnomeprintui2.2-dev
apt-get install libpanel-applet2-dev libgtksourceview-dev
apt-get install libgtkhtml3.14-dev

BUILDDIR=~/mono-build
mkdir -p $BUILDDIR
cd $BUILDDIR

wget http://go-mono.com/sources/libgdiplus/libgdiplus-1.9.tar.bz2
tar xvf libgdiplus-1.9.tar.bz2
cd libgdiplus-1.9
./configure --prefix=/usr/local
make
make install
cd ..

wget http://go-mono.com/sources/mono/mono-1.9.1.tar.bz2
tar xvf mono-1.9.1.tar.bz2
cd mono-1.9.1
./configure --prefix=/usr/local
make
make install
cd ..

wget http://switch.dl.sourceforge.net/sourceforge/nant/nant-0.86-beta1-src.tar.gz
tar xvf nant-0.86-beta1-src.tar.gz
cd nant-0.86-beta1
make install --prefix=/usr/local
cd ..

wget http://go-mono.com/sources/gtk-sharp210/gtk-sharp-2.10.4.tar.bz2
tar xvf gtk-sharp-2.10.4.tar.bz2
cd gtk-sharp-2.10.4
./configure --prefix=/usr/local
make
make install
cd ..

wget http://go-mono.com/sources/gnome-sharp2/gnome-sharp-2.16.1.tar.gz
tar xvf gnome-sharp-2.16.1.tar.gz
cd gnome-sharp-2.16.1
./configure --prefix=/usr/local
make
make install
cd ..

wget http://go-mono.com/sources/gtksourceview-sharp2/gtksourceview-sharp-2.0-0.12.tar.bz2
tar xvf gtksourceview-sharp-2.0-0.12.tar.bz2
cd gtksourceview-sharp-2.0-0.12
./configure --prefix=/usr/local
make
make install
cd ..

cd mono-1.9
wget  http://go-mono.com/sources/monodoc/monodoc-1.9.zip
unzip monodoc-1.9.zip
cd monodoc-1.9
./configure --prefix=/usr/local
make
make install
cd ../..

wget http://go-mono.com/sources/mono-tools/mono-tools-1.9.tar.bz2
tar xvf mono-tools-1.9.tar.bz2
cd mono-tools-1.9
./configure --prefix=/usr/local
make
make install
cd ..

wget http://ftp.novell.com/pub/mono/sources/mono-debugger/mono-debugger-0.60.tar.bz2
tar xvf mono-debugger-0.60.tar.bz2
cd mono-debugger-0.60
./configure --prefix=/usr/local
make
make install
cd ..

wget http://ftp.novell.com/pub/mono/sources/heap-buddy/heap-buddy-0.2.tar.gz
tar xvf heap-buddy-0.2.tar.gz
cd heap-buddy-0.2
./configure --prefix=/usr/local
make
make install
cd ..

wget http://ftp.novell.com/pub/mono/sources/mono-addins/mono-addins-0.3.1.tar.bz2
tar xvf mono-addins-0.3.1.tar.bz2
cd mono-addins-0.3.1
./configure --prefix=/usr/local
make
make install
cd ..

wget http://ftp.novell.com/pub/mono/sources/monodevelop/monodevelop-1.0.tar.bz2
tar xvf monodevelop-1.0.tar.bz2
cd monodevelop-1.0
./configure --prefix=/usr/local
make
make install
cd ..