I thought I'd post my findings after struggling with my washer on and off for the good part of the year.
I think I've found an uncommon solution to E01 F09 long drain error, and maybe the cause of the "SUD" error for excessive suds. Washer had intermittent problems stopping with the E01 F09 error. After a while, it was every cycle and was impossible to wash a load. First thing I did was check the pump trap and all discharge hoses. My particular model didn't have an access door at the bottom front, so I had to remove the entire panel. There was quite a bit of debris caught, but looked like there was still plenty of areas for water to bypass. I removed all discharge hoses and took them outside and sprayed through them with the garden hose. Some stuff came out which was caked to the sides of the tube, but nothing crazy. The washer seemed to work for about another month, then started the same thing again. Thinking I had some kind of drive motor failure, I wanted to give it one last shot before ordering a new motor. From the little info I could find, here is how the washer comes to the conclusion that it's not draining enough. When the cycle is first started, it logs the amperage (or some other form of measurement using the motor) as it tumbles the clothes for a few seconds. When the clothes have been washed, drained, or at some points in between, it also takes note of the amperage, and can verify that there is still too much water in the drum. The heavier the load saturated by water, the more amps are drawn by the motor in order to turn it. If it's outside of the programmed threshold, it flags an error. My washer had no sensors which could detect water level, it's done using the drive motor readings. It would make sense that a faulty motor would be the cause of the errors, and looks like it was in some cases.
Moving on with my diagnosis, I checked the discharge pump operation by watching the discharge pipe and lifting it out of the standpipe to verify that water was easily coming out, and that my standpipe itself was not backing up with water. That looked fine, so I took troubleshooting a step further and removed the pump completely, and the rubber bellows connecting to the bottom of the drum. I inspected the pump impeller and reached up into the drum as far as I could to check for anything that may have gotten stuck in there, but all looked good. I once again removed the discharge hose/hoses and blasted them out with the garden hose, but I noticed something when I did it this time.... It was almost like I heard and felt a faint "pop" when blasting the hose to clean it out, and seemed to flow water through a little more. There seemed to be a one way valve inside the hose, if I remember correctly, water would only go through one direction. I didn't give it much thought at the time.
SOLUTION
After assembling everything, the washer has been fine for about 6 months now. After giving it some thought, I'm wondering if the problem all along has been a sticking check valve in the discharge hose. After looking through all parts of the washer, that is the only logical explanation as to why I had gotten the error twice, and not really finding anything obvious which would have clogged the system, other than the faint "pop" and release of pressure from the discharge hose. I didn't experience this "pop" the first time I cleaned out the hose. It's worth a shot if you are having these issues.