I had a biopsy half the prostate is benign cyst the other half is cancer gleason 9 can I have a pvp to open the urethra up?

Prostate cancer. You could have a pvp or TURP but what treatment are you considering to definitively treat your cancer. High grade aggressive cancer needs aggressive treatment if it is confined to the prostate. Radiation or radical prostatectomy is indicated if your staging workup is negative(ct/bone scan) if this has already spread, hormonal therapy should be started soon good luck.
Here are... Clinically, you had life dilemma with two neck-to-neck priorities to choose between high-risk prostate cancer and urinary retention. To help understand how to take on such, the following may be useful: there's no magic in life/medicine; if any, that is to apply current available knowledge, skills, technology, drugs, common sense, ; wisdom at reasonable time and way to reasonable patient.
Treat the cancer. You can, but if you are having problems urinating, then treating the prostate cancer will likely open the urethra and allow improved voiding. Pvp will open the urethra but will not treat the cancer.
If necessary. If your cancer is advanced enough, you may not be a candidate for local treatment (i.e. Surgery). In this case you were likely offered testosterone lowering injections or testicle removal. At that junction, the lack of hormone may dramatically decrease the prostate size and allow for easier voiding in the next 2 to 3 months. If not, a local procedure like pvp is an option for quality of life.