Just installed the i800 (not much difference between the 800 and 900) and it was a breeze I hope you got the optional hayabusa specific wiring harness kit as the one they ship with the alarm requires you to do some wire splicing, get the kit its plug and play. So here are the steps I took
1. Lay all the parts out on the floor without physically connecting them so you see how the parts go together.
2. Connect the MCM using the velcro in a good location
3. Connect busa harness kit between turn signal/brake Light connector
4. Connect busa harness kit to HAR1
5. Connect HAR1 to + battery terminal
6. Plug HAR1 into MCM you will hear alarm chirp
7. Velcro to safe location the RFID module and tuck away/zip tie any loose cables or wires
8. Plug in and position the perimeter sensor if you chose the option don't velcro into position until you have tested it and set the sensitivity, I used painters tape to hold it temporarily for testing then velcro when done
I did not buy the disable module, I may in the future hell I'll order it now
All in all it was an easy install
Feel free to pm me if you need more help.
My bike is in storage so sorry for the lack of pix