If sailing mostly in 8-10 knots, I think you should keep the formula board. ( but OK I weight 95 kg, so the lightweights’ know better )
Regarding CR vs. OD it’s hard to say, it depends on pumping technique and wind quality.
A guess, min. 1 knot (2 knots when passive rider) earlier planning for OD and the same in favour for CR in high wind.
Experience from a pro rider is, OD 10,0 planes as early as 11,0 CR.
OD has easier handling on the water and a bit softer. This is in favour for a lightweight rider.
The CR excels when going super fast and maxed out through chop.
On flat water or more regular wavy conditions I don’t think you can feel any differences.
You would have changed a size down long before. So in 13 knots you won’t feel a diff., in 16 to 20 knots yes.
10,0 and 8,5 is perfect quiver for lightweight on Formula, but on IS133 or maybe Futura 144 too.
If you choose CR, go for 2008. Take the Redline Mast (100% carbon) no matter if OD or CR.