You mention that there was nothing else reported in the biopsy report.
> What about the MRI report - was there any mention about extracapsular extension, seminal vesicle invasion, or perineural invasion?

Note that with a Gleason 9 (very high-risk disease), the NCCN guidelines recommend doublet therapy (both ADT and ARPI) with external radiation (your Alternative 1). (See attached NCCN Guidelines chart.)

As you mention, the final treatment decision depends on the outcome of your PSMA PET scan.

For my localized, Gleason 7(4+3), PSA of 7.976, I used SpaceOAR Vue for my 28 proton radiation treatments. (SpaceOAR Vue is an enhancement of the standard SpaceOAR Hydrogel, containing approximately 1% iodine bound to the hydrogel to be more visible under CT scan.) Studies show that SpaceOAR not only reduces rectal radiation dose, but also reduces late GI and GU toxicities, and provides urinary, bowel, and sexual quality-of-life improvement: https://pubmed.ncbi.nlm.nih.gov/34029607/

For localized disease and with success rates being statistically equivalent, the decision about which treatment to use (external radiation vs surgery) often hinges on what side/after-effects you’re willing to deal with.
As usual, discuss all this with your medical team.