I doubt that you have given us enough data to guess.
The total length of the foot is only one of many parameters affecting the foot. The full 3D shape of the foot matters a lot, as do the points and degrees of flexibility. For example, if your ankle area is thinner or fatter than the boot maker assumes, that can big a big problem. One well respected fitter told me that the distance from the heel to the ball of the foot is typically more important than the total, because most boots bend upwards at the estimated position of the ball of the foot. An incorrectly positioned bend could lead to serious pain or injury, and, if you use "standard" blade placement, may also make balance and control difficult if the position of the ball doesn't approximately match the point at which the blade curvature changes. Heel height can be a huge deal.
I personally would choose a slightly large size - but that is because I am willing and able to reshape or remake the insole and boot in fairly substantial ways, using a variety of methods and tools, to make it fit, and am willing to use non-standard mounting positions for the blade, and to reshape the blade a little. Having space inside the boot means it is easier to reshape it. In contrast, significantly stretching leather is limited, tends to be temporary and in extreme cases needs to be repeated often. Non-leather boots may be even harder to reshape.
Exactly what is wrong with your older boots? (Assuming this isn't your first pair.)
If you have an old skate pair that is almost still stiff enough and fits well enough, maybe you can make do for a little while, until an open shop with the right sizes becomes available? At one point, I wrapped duct tape around boots to stiffen them - but I had to tear or cut it off every time I skated. I also played at other points with using thicker socks, and with gluing reinforcing material inside boots.
Is there another open shop with first class fitters within a plausible driving, train or flying distance (say, a few hours)?
Another factor is the fitter (i.e., skate tech). If the fitters you used are very, very good, they might be able to guess better than if they are average fitters. Fitter skill is such a major concern that many skaters drive for many hours, or fly half way around the world to get what they feel is the best available fitter. If I were buying today, I would probably do something like that, because my history includes serious misfits. I would personally avoid average skill fitters regardless. If you read past posts on this forum, you will find a fair number of people who bought 2 or 3 pairs of boots before they managed to get a reasonably good fit - and in many cases, that could be blamed on the fitter. Also, good skate techs can somewhat modify boots in certain ways - and are more willing to return boots that weren't built to proper size. I economize on almost everything - but boots are probably the wrong place to do that.