CBSE Class 9 and 10 are the foundation of higher classes. So, it's important to keep your base strong. Here are some reference books that will help you in your exam preparation - https://www.aakash.ac.in/blog/best-books-for-class-9th-and-10th/
Aakash Blog
Best Reference Books for Class 9 & 10th CBSE Students
Best books for CBSE: Here are the best reference books for class 9 and class 10 CBSE Students, some benefits of studying from the these books and more on aakash
Olympiad exams help students in improving their problem solving skills, which in future help them to prepare for competitive exams. Here are some important tips & tricks to prepare for Maths Olympiad exam - https://www.aakash.ac.in/blog/olympiad-exam-preparation-7-essential-tips-for-class-9-maths/
Aakash BYJU'S Blog
Olympiad Preparation Tips: 7 Essential Tips & Tricks For Class 9 Maths
Olympiad Preparation Tips: Olympiad exams help students in improving their problem solving skills, which in future help them to prepare for competitive exams.