Sun Square Pluto...

starts on September 25 (using a 1 degree orb), is exact on September 26 at 10.26am in Kilmore, leaves on September 27.  Sun at 2 degrees and 49 minutes of Libra, Pluto at 2 degrees and 49 minutes of Capricorn.

This aspect intensifies the energies that were around a few days ago at the Full Moon, because they were within range to form an aspect back then.

A square aspect usually produces tension and sometimes conflict between the people and/or situations represented by the two planets involved... in this case the Sun and Pluto.  However, this tension can be positive in that helps us identify the root cause of a problem, meaning we can do something about it and reach a turning point in whatever is going on.

Being in cardinal signs, this suggests that there will be physical action taken... although this would depend also on which houses this aspect falls in within your own birth chart.

As usual, look at which houses are ruled by the Sun (one with Leo on the cusp) and Pluto (one with Scorpio on the cusp) to get a feel for what or who may be involved: as well as which houses these planets fall in.

If you have personal planets and/or points in Libra and/or Capricorn then you may be more sensitive than others to this transit.