>Nintendo had dial up modems and their own intranet in 37% of Japanese households in the mid 80s?

That Wikipedia link says that the Famicom (NES) was in 37% of households. Nintendo only shipped 130,000 modems, a tiny percentage of the total Famicom units sold.

SNES was 90s iirc?

Yes, I believe it was, but this peripheral and the software was (unless I read or interpreted incorrectly) designed for the original NES.

(There is a note that there were remakes of the horse race betting software for SNES and Dreamcast)

Not the Famicom according to GPs wiki.