Deane, you can project the lyrics from your keyboard or from your iPad, or your laptop, if you are using one. All three need a conversion wire to meet the needs of what you are connecting to, and from.
The laptop is the easiest one. HDMI wire from laptop to the TV. The Sx900, and the iPad need a conversion wire. You can Google to find the information for both, and in the Sx900 manual.
I find the most difficult to use is the Sx900. The Laptop and iPad are easiest. My favorite is the iPad, with the On Song App.
Question: What are you using to display your music and lyrics now? If you are using books, you would have to scan each song and load them into an iPad, or the laptop.
Hope this helps, John C.