Hi, using a rub inside the viv would be better as you could more closely monitor their eating, pooing etc. Even better would be to have the rub completely separate with its own heatmat / stat but that might not be possible for you? I think that they could do with weighing again as 5g would be VERY small at 9 weeks - I would expect mine to be that weight at 1 to 2 weeks. Although they have been incubated for female (sorry but SOME breeders will tell you this anyway) there is still a risk that they might not be, so until you are sure it is better to keep them apart imo.
Once they are older, obviously female and better established it should be possible to re-introduce them which would be lovely.