I have a tilt bed trailer. I have winched a fair number of vehicles onto it. I started with a small winch similar to those used for fairly large boats. It required a ****** block for most vehicles, but using a ****** block basically doubles the pulling power. Now I have a Warn 8000 lb power in only antique given to me by my son. It is fast, faster than I need, and I have never needed to use a ****** block. IMHO, a 9,000 lb winch is overkill unless you want to load a loaded 3/4 ton pickup without using a ****** block.
How are you going to power the winch?? A dedicated battery mounted on the trailer? You have to make sure it is charged, and it's another battery to buy/maintain. I use the tow vehicle battery and have a 20+ foot heavy gauge welding cable to reach the battery on my Suburban, x'cab pickup, or K-5 Blazer. I leave the engine running and if I remember, turn on the headlights. My 30 year Toyota mechanic buddy says this kicks the alternator in the ****, I dunno. I only use a long lead for the positive leg and sometimes the trailer hitch is sufficient for the ground. If not, I use a jumper cable to the tow vehicle's frame. I think if I were buying, I'd stay at or under 5,000 lbs. If you're inclined, you can then carry the winch inside. When I was using the smaller winch, I used a plate that attached to a trailer ball mounted to the front of the trailer that allowed me to store the winch inside. With the Warn, it is (semi)-permanently mounted to the front of the trailer and I cover it with a HF plastic tarp and a bungee cord. The bigger the winch and load, the more power it will draw, meaning serious amps. You need a switch heavy enough to handle the current. I tried a HF remote, didn't like the way it sometimes didn't work. Seemed like it didn't want to handle the high current.
If your trailer doesn't tilt you'll have to pull the vehicle up, probably need a little more pull up the ramps. Of course this depend on the length of the ramps and the height of the trailer. Sometimes you can take advantage of the terrain and use a hill or rise to help. Even so, a 5,000 lb winch with a block would generate 10,000 lbs (theoretically). Unless you're loading 2- ton trucks it should work.
Good luck.