Note: I am starting a new portion of my website that intends to answer the many questions I often receive. These frequently asked questions (FAQs) will be linked and included with the "Contact, Orders, FAQ" menu. I will be copying and pasting these in their entirety here, too. I intend to make the answers thorough, so I will be adding them one at a time. Stay tuned...
9 pairs of planes is not likely the perfect place to start for somebody first considering these tools; 1 pair is also not likely ideal. I always recommend starting your collection of hollows and rounds with 2 pairs.
These sizes are a good size for somebody that makes small to mid range (chest of drawers) furniture and will ultimately be included in the largest highboys, secretaries or case clocks.
You will, of course, need a method for creating rabbets that is both accurate and efficient.