Don’t sweat the radiation being too late, you are a little late, but not significantly.

From Ascopubs about what PSA to do salvage radiation.

≤0.2 ng/mL:
Starting at this level maximizes disease control and long-term survival. Patients treated at PSA < 0.2 ng/mL achieve higher rates of undetectable post-SRT PSA (56-70%) and improved 5-year progression-free survival (62.7-75%).
Delaying SRT beyond PSA ≥0.25 ng/mL increases mortality risk by ~50%.

0.2–0.5 ng/mL:
Still effective, particularly for patients with low-risk features (e.g., Gleason ≤7, slow PSA doubling time). The Journal of Clinical Oncology recommends SRT before PSA exceeds 0.25 ng/mL to preserve curative potential.

0.5–1.0 ng/mL:
Salvage radiation remains beneficial but may require combining with androgen deprivation therapy (ADT) for higher-risk cases.

This article discusses the above;
https://ascopost.com/news/march-2023/psa-level-at-time-of-salvage-radiation-therapy-after-radical-prostatectomy-and-risk-of-all-cause-mortality/
The SRT will probably bring your PSA back to undetectable. Are you already on ADT or an ARSI? With a Gleason nine and having a reoccurrence, you normally want to have both of those drugs. If you have a choice, tell the doctor you want Orgovyx A pill you take once a day for ADT.. Once you stop, your testosterone comes back quicker than with the other drugs. They will probably put you on Abiraterone (Zytiga). If they want to put you on the lutamide Instead, you should tell them you want Darolutamide, It has the least side effects and doesn’t pass the blood brain barrier. You have to be proactive and say what you want, Let the doctors know you understand the differences and that is your choice.

I had eight weeks of SRT and had no side effects at all at the time. I had it first thing in the morning and went to work right after worked a full day without any problems. If you’re having less time doing it, then they give you more radiation and the side effects can be more problematic. Usually, you have urinary issues and fatigue when you’re getting a lot of radiation. If you have problems, let them know right away, They can always change the dosage.