Your Dad's diagnosis is almost identical to mine, Gleason 7, PSA 9.6 this time last year.
I was given a bone scan too, which was clear. The Consultant, in the report wrote.., "bone scan clear, as would be expected at this (PSA) level."
Diagnosis is always a shock and stressful, but it would be unlikely to have spread to the bones at this low PSA.
1 year post diagnosis and treatment, RT and HT, my PSA is rock bottom and life is back to normal.