Sorry to hear you are experiencing problems.
I just had a look at the crash log. Unfortunately it is inconclusive. It tells me a background thread crashed over a memory management problem. No HoudahSpot code is directly involved in the crash. This is not to say HoudahSpot is not at fault. It probably is. But the mistake happened earlier and only becomes fatal in a later clean-up.
Is there any particular action that always precedes the crash? E.g. closing a window.
Did you have any preview or inspector windows open when HoudahSpot crashed?
Which columns does your search show?
Are you using the "Total Size" column? This value is not stored by Spotlight or the file system. This is computed by HoudahSpot as the sum of all folder contents. This takes some time and effort.
HoudahSpot 3.9.5 should do a better job than 3.9.4 at loading and caching values for the columns. Scrolling should be smother on 3.9.5 than on 3.9.4.
Houdah Software s.à r.l.