They might not do a bone scan - some hospitals only do that if they suspect that it has spread and the fact that it is to be discussed at the next MDT on Friday suggests that they are not waiting for a bone scan or PET?
You have remembered correctly SLF. Your Gleason score is a 9 which usually means that either the majority of cells were a 5 but there were also some 4s OR the majority were 4s but there were also some 5s. Sometimes the results seem confusing because they talk about the Gleason grades ( a description of how distorted the cells look under a microscope - a 3 or a 4 or a 5) and the Gleason score (the sum of the two most common patterns such as 4+5 or 5+4); in your case, there were a lot of 3s (which is reassuring) but they don't want to ignore the 5s so have given you a higher total. The meeting next Friday is the multi-disciplinary meeting, involving urologists, oncologists and other specialisms such as radiology - together, they look at all the diagnostics (your scans, biopsy results, etc) and form a view about which treatments might be suitable. Then someone will tell you what the MDT view was - as stated above, you might be told that surgery, radiotherapy or brachytherapy would all be suitable, or you may be told that one treatment is going to be better for you than others. Assuming you are given a choice, you then ask for an appointment with a urologist and a separate appointment with an oncologist to discuss the treatment, potential side effects, likelihood of success, etc and then you make a decision about which treatment you want to go for. This is where the PCUK toolkit mentioned above comes in handy - all treatments have side effects and you end up having to decide a) which treatment gives you the best chance of full remission and b) whether you can live with the potential side effects of that particular treatment.
Things will seem better once you have the full diagnosis and a treatment plan. My dad was diagnosed nearly 25 years ago and my husband 13 years ago.