There's a well-known article for solving graph isomorphism problem in polynomial time. Many other articles on the subject of isomorphism mention it as a possible "alternative", but note that is not applicable in general case and move on presenting their approach.
However, I'm interested in solving subgraph isomorphism in the context of chemical structures. Majority of graphs in this domain are, in fact, of bounded degree. This is a result of chemical properties, where bonds (edges) are result of valence electron pairings. Because there's only limited number of electrons on valence shelve, so is the number of edges limited. I doubt there are chemical structures where atom has more than 7 bonds. Even if such exotic example would arise, it would be easy to identify and use more general algorithm for it.
The problem is I didn't find any practical implementation of the polynomial-time algorithm or any follow up work that would consider the idea from more practical perspective. The established algorithm for subgraph isomorphism in chemoinformatics seems to be VF2. There were some other related questions asking for a more digestible explanation, but I'm specifically looking for implementation and why can't I find any. Is the approach somewhat obsolete, forgotten, too hard to explore, or is there other issue why not use it?