If you already have access to the PDF, here are tips to use it effectively:
Having the PDF is useless unless you use it correctly. Here is a 4-step strategy: S Chand Physics Class 9 Free Download Pdf
Step 1: Read NCERT First Never start with S. Chand. Read the NCERT Physics section (1 page per topic). It takes 30 minutes. If you already have access to the PDF,
Step 2: Deep Dive with S Chand Open the corresponding chapter in S. Chand. Read the "Theory" section. Lakhmir Singh explains concepts that NCERT assumes you know. Having the PDF is useless unless you use it correctly
Step 3: Solve "Questions Based on High Order Thinking Skills (HOTS)" This is the most important section in the book. These are the exact type of tricky questions that appear in the final exam to differentiate a topper from an average student.
Step 4: Numerical Practice Do every numerical problem at the end of the chapter. If you get stuck, S. Chand provides a separate "Solutions" book (free PDFs available legally for solutions only).
Instead of looking for pirated versions, consider these legitimate alternatives: