Fishing from a boat or the rocks?
Fishing for trout or sharks?
Lures or chunking whole mullet?
Anything from a 10ft fly rod to a boat rod with roller guides and a 16/0 penn full of 130lb line could be appropriate for some sort of jetty fishing. You really need to narrow down what you are after. Maybe the best starting point to consider would be budget and your skill level. Spinning does help narrow it down a little.
There is just a huge variety of fish swimming around the jetties and what will work for one species probably won't be too effective for another.
Another consideration is if this is a one time thing or something you plan to do a lot more of.
ANy pawn shop near the coast will have a lot of cheap used tackle that will work fine for the occasional angler, if it's the start of a new hobby, get the best you can afford.
A longer rod is always useful around the jetties, makes it easier to maneuver fish/tackle around the rocks. One of may favorite rigs was an 8 foot rod/penn 650 spinning rreel with a load of 15 lb and 20 ft or so of 50lb leader. Medium weight fast action rod. Faster action rod just lets you handle a wider range of weights with a trade off being loss of hook setting power. Everything is a trade off.
From the rocks for now. My skills are pretty good. I have been LONG RANGE fishing in San Diego for 15 years. Haven't jetty fished since I lived in FLA. 25 years ago.I have Accurate reels from the 270 up to ATD 50. I just bought Stella 18K and 20K. I just figured that I might need something a little lighter for the Jettys. Never fished in that area. Moving to Rockport in 2 weeks
My best friend and I have fished the jetty's for sometime in Port A. before I got a boat. We still go out there and fish them but in the boat now. You can see quite a bit of action out there in the summer months. We use Falcon rods that are either 7" or 7'6" in length. We both use Symetre, Stradic and Saros reels that are the 2500's and 4000's in size. I like to use Power Pro braid in either 20 or 30 lb test, (depends on what we are fishing for). We like the lighter tackle gear because it's alot more fun and challenging to fight the fish. You can use quite a bit of different gear out on the jetty. It really comes down to personal preference.