I wouldn't bet anything on new routes like these. They are not likely to be busy, and Flybe's business model needs bums on seats. BLK simply will not do that unless it pulls bums off the LPL services. a 19 seater works well to both BLK and BHD.
Any planning would be for at least a year hence by now. S09 is sorted, and W09 would only be a reduction in frequency to match demand. Certainly not new routes.
S10? You never know.
Exeter has far bigger fish on the fryer right now to put too much into messing about with the IOM operation. It's ticking along nicely and the reliability is nearly the best in the network.