The best exclusive editions have hyperlinks. You click on "Chapter 12: Heron's Formula," and it takes you immediately to the solutions. This saves hours of flipping pages during late-night revision.
While the PDF is convenient for searching specific solutions on the go, Class 9 Maths requires solving diagrams (Geometry/Constructions). It is highly recommended to use a physical book for actual practice to simulate the exam environment. xamidea class 9 maths pdf exclusive