I do not think that growing is difficult, but extracting the oil from it in such a way that it will have a correct composition is likely to be impossible without complex chemical equipment.

For growing it would be difficult to obtain a good strain. The strains used by commercial producers were originally isolated from some mangrove forests or other such places on sea shores, but then they have passed through years of selection and/or gene manipulation. Even when a good strain would be available, a culture that is grown in less controlled conditions could be susceptible to being wiped out by a disease, I have no idea.

In any case, I think the difficulty is in the oil extraction, not in the culture. In industrial conditions the extraction could be made with supercritical carbon dioxide, for maximum cleanness of the extracted oil, but that would not be feasible at home. Using an organic solvent, like hexane, might be possible at home, but that would be dangerous and there is the risk of contamination of the edible oil with solvent residues.

Accurate chemical analysis of the oil would be needed, to determine the fatty acid profile and validate the extraction method.