BGS is BGS, PSA is PSA. They grade to slightly different standards. A BGS 9.5 could be a PSA 9 or could be a PSA 10. Most people would probably agree with the following:
BGS 10 > PSA 10 > BGS 9.5 > PSA 9
for me I think this general trend is useless though. There’s so much variance within each grade and differences how each company will dock based on something (for instance, centering). Some people might make up some arbitrary rule based on subgrades but personally, I would judge each card individually. This is just my own opinion
further reading:www.elitefourum.com/t/are-bgs-9-5-actually-equal-to-psa-10/27723/1