Ancient architects and engineers were fantastically ingenious. People were doing stonework with the same tools available thousands of years ago until the 19th century brought steam power.
900 years ago, the Great Pyramid of Giza was 3,600 years old.
The hypostyle hall at Karnak was 2,200 years old/
The intricate stonework in the medieval cathedrals was done 900 years ago.
Regarding the turning on the Indian columns, you could build a cylindrical wooden frame around the rock and spin the cutting tool around it.
If the rough column was lying down, you could cut the top half into a semi-circle (semi-cylinder?) and then turn it over and finish. But with the varying diameter on the Indian columns, I think it would be easier to cut standing up, with the cutting making full circles.