Yes a soul purpose can be seen from a horoscope but there are various factors you will need to analyse in order to find that out.
1.You will need to analyse the Bhrigu Bindu(Mathematical point between Rahu and Moon)
2.Look at the placement of Atmakaraka
3.Look at the placement of Amatyakaraka.
4.Look at the Karakamsha and Swamsa lagna.
5.Look at the Ascendant and Moon nakshatra.
After you analyse all these factors then you can find out a persons Destiny in this lifetime.