Hi Pete
Welcome to IIS
By the way, good choice on the 10" DOB. Nice scope !
Lets start by saying ...Bintel sell quality equipment.
However, they sell both good starting equipment for budget minded
and they sell extra good equipment for the more affluent.
So your eyepieces are certainly good (but for investments from around $350 to $1000 (each) you can get best).
Some say the increase costs are not proportional to the improvement in view.
Others disagree
For starters, I am confident that the eps you have will be good quality plossls.
Before spending any more I suggest you get along to an observing session and talk to others and try some to see how they perform in your scope.
(Have a look in the star parties forum to see if any are near to you).
The 9mm will be best for planetary details.
The 30mm will be best for most larger Deep Sky Objects (DSOs)
So my advice is hold off for a while and get the most from what you have now.