Some random thoughts...
Carry things...sandbags, farmers walk bars, rocks, barrels.
If you have a sled, pull it in all directions. If you don't have a sled, make one.
I suggest working on low to medium rep ranges, and think about doing EDT style workouts to keep the pace up.
Sprint. Sure, run your 40's but also run 5s, 10s, 20s, 50s, 100s...work on your lateral speed....
Work on the movements of whatever position you are...ex., if you are a DB, backpeddal.
They will prob. test your bench by 225 for reps. Up your max strenth in the bench and your reps will go up.
They'll test your 40...improve your running form and your time will go up...and I'm sure you know that prost. chain work is vital.
They will most likely give you the 10yd shuttle run. Stay low, dont spin, and drive thru the cones.
Frankly, I think tests are BS but, you gotta do them.
Given the fact that you already lift, and if you run for the next 9 months, you will be more in shape than 95% of the other guys. Don't worry about your age...I played on a team with a DL who was 52. He was a role player but ended up being 2nd on the team in sacks. I won't say who was first haha.
Some tips for the actual league play.
-You will come across quite a few jackoffs. Guys who are all talk and no play. Ignore them, someone on the other team tends to take care of these people.
-There will be quite a few "bush league" types who are out of shape, and are there mainly to start fights. Ignore them.
-The talent level will range from fromer pro players to guys who've never played before. Overall, however, you'll be surprised at how good the games are. I'd say the speed of the games is typically that of a Div. Iaa college game. Maybe Div. II, depending on the league. Remember though, these are grown men flying around...there will be some explosive hits.
-You'll have fun. For all the bad stuff that goes on, there's nothing like playing a game, getting beat up, then going out with your team mates and their families, friends etc, and eating and having some drinks.