The flowers don't help much with differentiating between Glycine species. This does look like tabacina in that the central leaflet in each leaf is on a longer stalk than the two side leaflets. However, based on habitat G. clandestina is more likely (usually in forest and tabacina in woodland/grassland). I was surprised to find quite a bit of tabacina-like foliage on new growth in the Eurobodalla area myself and I think it would be good to get some new photos of the plants now they are more advanced to see if the leaves have changed as the plant matures. Also clandestina foliage tends to have a glossier surface than tabacina.