The growth compares favourably to 7.7 per cent recorded in the Jul-Sep quarter in 2008.
The Indian economy grew especially due to a good showing by the industry and the services sector.
Earlier, Finance Minister Pranab Mukherjee, the Reserve Bank and the Planning Commission had predicted a growth of about 6-7 per cent, while global agencies and analysts forecast it to be even lower.
The manufacturing sector grew by 9.2 per cent in the Jul-Sep period compared to 5.1 per cent in the corresponding period of last fiscal.
Community, social and personal services expanded by double digit at 12.7 per cent against 9 per cent.
Despite being affected by international slowdown, trade, hotels, transport and communication sector grew by 8.5 per cent.
Financing, insurance, real estate, and business services rose by 7.7 per cent against 6.4 per cent.
Electricity, gas and water supply was up 7.4 per cent compared to 3.8 per cent. Construction rose by 6.5 per cent, down over 9.6 per cent in 2008.