Mentioned inverter design can handle between 50-100W, with adding more MOSfets in parallel you can increase power. Of course transformer must be adequate.
For 50-100W you need transformer for that.
9V x 6A = 54W
9V x 10A = 90W
Try to get transformer between 6-11A with 9V on secundar winding.
I dont think that is smart to take this like projects for first project. This can save you money and time, and maybe health or even life. Its good to be in this topic, and to not be chicken, but its need to know and have some basic knowledge about currents and safety.