How to create a custom CRS using EPSG transform method 9666 (P6 I=J+90 seismic bin grid coordinate operation)

[yportier]

I am trying to recreate the EPSG example of georeferencing I=J+90 local bin grid using the P6 I=J+90 seismic bin grid coordinate operation (EPSG code 9666) but the resulting CRS can't be used to transform coordinates.
xform = Transformer.from_crs('EPSG:25832', my_crs) fails with ProjError: Input is not a transformation.

Here is the wkt string I'm using to create the crs with my_crs = crs.CRS.from_wkt(wkt):

DERIVEDPROJCRS["seismic survey bin grid",
    BASEPROJCRS["WGS 84 / UTM zone 31N",
        BASEGEOGCRS["WGS 84",
            ENSEMBLE["World Geodetic System 1984 ensemble",
                MEMBER["World Geodetic System 1984 (Transit)"],
                MEMBER["World Geodetic System 1984 (G730)"],
                MEMBER["World Geodetic System 1984 (G873)"],
                MEMBER["World Geodetic System 1984 (G1150)"],
                MEMBER["World Geodetic System 1984 (G1674)"],
                MEMBER["World Geodetic System 1984 (G1762)"],
                MEMBER["World Geodetic System 1984 (G2139)"],
                ELLIPSOID["WGS 84",6378137,298.257223563,
                    LENGTHUNIT["metre",1]],
                ENSEMBLEACCURACY[2.0]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]]],
        CONVERSION["UTM zone 31N",
            METHOD["Transverse Mercator",
                ID["EPSG",9807]],
            PARAMETER["Latitude of natural origin",0,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8801]],
            PARAMETER["Longitude of natural origin",3,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8802]],
            PARAMETER["Scale factor at natural origin",0.9996,
                SCALEUNIT["unity",1],
                ID["EPSG",8805]],
            PARAMETER["False easting",500000,
                LENGTHUNIT["metre",1],
                ID["EPSG",8806]],
            PARAMETER["False northing",0,
                LENGTHUNIT["metre",1],
                ID["EPSG",8807]]]],
    DERIVINGCONVERSION["seismic survey bin grid",
        METHOD["P6 I=J+90 seismic bin grid coordinate operation",
            ID["EPSG",9666]],
        PARAMETER["Bin grid origin I",1,
            SCALEUNIT["Bin",1],
            ID["EPSG",8733]],
        PARAMETER["Bin grid origin J",1,
            SCALEUNIT["Bin",1],
            ID["EPSG",8734]],
        PARAMETER["Bin grid origin Easting",456781,
            LENGTHUNIT["metre",1],
            ID["EPSG",8735]],
        PARAMETER["Bin grid origin Northing",5836723,
            LENGTHUNIT["metre",1],
            ID["EPSG",8736]],
        PARAMETER["Scale factor of bin grid",0.99984,
            SCALEUNIT["Unity",1],
            ID["EPSG",8737]],
        PARAMETER["Bin width on I-axis",25,
            LENGTHUNIT["metre",1],
            ID["EPSG",8738]],
        PARAMETER["Bin width on J-axis",12.5,
            LENGTHUNIT["metre",1],
            ID["EPSG",8739]],
        PARAMETER["Map grid bearing of bin grid J-axis",20,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8740]],
        PARAMETER["Bin node increment on I-axis",1,
            SCALEUNIT["Bin",1],
            ID["EPSG",8741]],
        PARAMETER["Bin node increment on J-axis",1,
            SCALEUNIT["Bin",1],
            ID["EPSG",8742]]],
    CS[ordinal,2],
        AXIS["inline (I)",eastSouthEast,
            ORDER[1],
            SCALEUNIT["Bin",1]],
        AXIS["crossline (J)",northNorthEast,
            ORDER[2],
            SCALEUNIT["Bin",1]],
    USAGE[
        SCOPE["Navigation and medium accuracy spatial referencing."],
        AREA["Between 0°E and 6°E, northern hemisphere between equator and 84°N, onshore and offshore. Algeria. Andorra. Belgium. Benin. Burkina Faso. Denmark - North Sea. France. Germany - North Sea. Ghana. Luxembourg. Mali. Netherlands. Niger. Nigeria. Norway. Spain. Togo. United Kingdom (UK) - North Sea."],
        BBOX[0,0,84,6]]]

Note: I asked this question on SO.

[snowman2]

The PROJ mailing list is a good resource for a question like this: https://lists.osgeo.org/mailman/listinfo/proj/