October 9 holds significance in Indian history for its association with the freedom movement, public institutions, defence and social leadership. The date is also remembered for the birth anniversaries of prominent Indians such as Gopabandhu Das, Minjur Bhaktavatsalam, Ustad Amjad Ali Khan, Keshub Mahindra, Anbumani Ramadoss and Sayani Gupta.

Among those who died on this day are Kanshi Ram and renowned music composer Ravindra Jain.
October 9 is also observed globally as World Post Day, marking the anniversary of the establishment of the Universal Postal Union (UPU) in 1874. In 2026, the theme is "World Post Day: One Postal Network, Infinite Possibilities."
One important event associated with October 9 is the formal inauguration of the Territorial Army in 1949. The Territorial Army was inaugurated by C. Rajagopalachari, the first Indian Governor-General, and became an important component of India's defence organisation.
On October 9, 1920, the institution that had earlier been known as the Anglo-Muhammadan Oriental College was renamed Aligarh Muslim University (AMU), marking an important milestone in the development of higher education in India.
Another notable milestone associated with the date is the beginning of International Foreign Service Day/Indian Foreign Service Day observance, linked to the establishment of the Indian Foreign Service in the post-Independence period.
Several notable Indians were born on October 9:
| Year | Name | Events |
| 9 October, 1877 | Gopabandhu Das | Freedom fighter, journalist, poet and social reformer popularly known as Utkalmani. |
| 9 October, 1897 | Minjur Bhaktavatsalam | Freedom fighter and former Chief Minister of Madras State. |
| 9 October, 1923 | Keshub Mahindra | Industrialist and former chairman of the Mahindra Group |
| 9 October, 1945 | Ustad Amjad Ali Khan | Celebrated sarod maestro and one of India's leading classical musicians |
| 9 October, 1955 | Shakti Singh | Actor and voice artist known for his work in Hindi cinema and television |
| 9 October, 1968 | Anbumani Ramadoss | Politician and former Union Minister for Health and Family Welfare |
| 9 October, 1985 | Sayani Gupta | Indian actress known for films, television and digital productions |
These personalities have contributed to Indian politics, public life, business, literature, music and entertainment.
Minjur Bhaktavatsalam, born in 1897, was a freedom fighter and later served as Chief Minister of Madras State. Anbumani Ramadoss, born in 1968, served as Union Minister for Health and Family Welfare and has remained active in Tamil Nadu politics.
Gopabandhu Das is another major political and social figure associated with the date. His role in Odisha's social reform and nationalist movement earned him the title Utkalmani.
Niranjana Nagarajan, born on October 9, 1988, is among the Indian cricketers associated with the date. She represented India in international cricket and played across formats during her career. She is also remembered for her contribution to women's cricket in India.
Kanshi Ram, founder of the Bahujan Samaj Party (BSP), died on October 9, 2006. He was an influential political leader whose work focused on the political representation and empowerment of historically marginalised communities.
Ravindra Jain, the renowned composer, lyricist and playback singer, died on October 9, 2015. Despite losing his eyesight at a young age, he established a distinguished career in Indian music and cinema.
Srihari Raghumudri, a Telugu actor known for his work in South Indian cinema, also died on October 9, 2013.
World Post Day is observed every year on October 9 to mark the establishment of the Universal Postal Union in 1874 in Bern, Switzerland. The day was officially declared World Post Day by the UPU Congress in Tokyo in 1969.
In India, the Department of Posts is observing National Postal Week from October 9 to 15, 2026, beginning with World Post Day. The 2026 theme is "World Post Day: One Postal Network, Infinite Possibilities."
October 9 brings together important chapters of India's political, educational, defence, cultural and sporting history. The date remembers personalities such as Gopabandhu Das and Ustad Amjad Ali Khan, while the deaths of Kanshi Ram and Ravindra Jain mark significant moments in India's political and cultural history. Globally, World Post Day highlights the continuing role of postal networks in connecting people, communities and economies.