Finally I have got a test setup:
Delete all occurrences of libngspice dylib and code models (analog.cm etc) in /usr and elsewhere except in KiCad installations. Delete installed Ngspice.
Restart the computer (seems to be important, there is some "memory effect").
Now I have KiCad 5.1.4 (most recent release build) and recent KiCad 5.9.9 (your suggestion from above) installed in parallel.
Starting 5.1.4 from eeschema: simulation of Sallen_Key o.k..
Staring 5.1.4 via KiCad app: crash as reported in this thread
Starting 5.9.9 via eeschema: simulation not o.k., code models (spice2poly.cm) are not found
Starting 5.9.9 via KiCad: simulation o.k. for Laser Driver and Sallen_Key!!
Finally I have got a test setup:
Delete all occurrences of libngspice dylib and code models (analog.cm etc) in /usr and elsewhere except in KiCad installations. Delete installed Ngspice.
Restart the computer (seems to be important, there is some "memory effect").
Now I have KiCad 5.1.4 (most recent release build) and recent KiCad 5.9.9 (your suggestion from above) installed in parallel.
Starting 5.1.4 from eeschema: simulation of Sallen_Key o.k..
Staring 5.1.4 via KiCad app: crash as reported in this thread
Starting 5.9.9 via eeschema: simulation not o.k., code models (spice2poly.cm) are not found
Starting 5.9.9 via KiCad: simulation o.k. for Laser Driver and Sallen_Key!!