Best vibration isolation device for cd player?

Feet or platform. I have a modified ModWright Oppo BDP 95 cd payer with external power supply. Thank you for your advice!
Don't forget to provide an acoustic shield around the player. Often that is more important then either the feet of platform. The acoustic energy that flies around a room and directly hits the cd player when you speakers are active can make a huge difference.
While there is much better and more expensive devices I found a combo of pico feet under and vibrapods on top of trap quite an improvement along with my mapleshade platform on my oppo.I would experiment with top and bottom vibration control by the transport of your oppo.
For my MW/Oppo 83 I use 3 vibrapod cones. They are $8 each and provide a dramatic improvement of clarity and detail. I tried their vibrapod isolators and they made my rig sound warmer, which was not the direction I wanted to go. I also tried a combo using both stacked- with the cones on top of the isolators. This combo provided a nice marriage of both characteristics which I really liked. My rig ultimately sounded best with the just the cones. Also know that there was some users who found that vibrapods produced a ring on the rack table. To counter this I use small index cards underneath the cone and this protects my rack.
Black Ravioli or Final Daruma
Yes Vibrapods for the money. Have been using them for years and absolutely flawless. From time to time you have to heat them in the oven on a cookie sheet as instructed to reinflate but it's so easy. Nothing to it.
I would suggest Herbies Tenderfooters under the External Power supply.I use 4 under my Thor Audio Linestage External Power Supply and they work very well for me..Nothing earth shattering for sonic improvement but noticable to my 66 year old ears......
A couple of years ago I allocated a solid week to coupling/decoupling devices for disk players and turntables, comparing about 20 different methods. For optical disc, magnetic levitation emerged as the sonic game-changer. The improvement was transformational, even on a (at the time) middling original Oppo bdp-83 doing Redbook and SACD duty. If your optical player is light enough, the Yeil Spike Sound Will levitation feet are affordable and effective. There are other more exotic ways to get mag-lev.

The 2nd most effective improvement for optical disc came from Aurios Classic Media Bearings, which are also relatively inexpensive in this realm. My listening tests were done on glass, MDF and 3-1/2" thick solid maple surfaces. The mag-lev solution was equally effective on all surfaces, nearly eliminating the sonic differences between them. Glass sounded as good as solid maple, with mag-lev. For Aurios, glass was not their friend, but differences between maple and MDF were sharply diminished.

For turntables, I found Aurios to be most effective, with mag-lev behind it, and much less practical given the mass of the turntable I used. Since I've done this comparo, the main significant new entry has been Black Ravioli, which I haven't tried yet.

With mag-lev, you have to match the support capacity of the devices to the weight of your player, and then work to arrange them equally around the center of gravity. Placement of maglev under the three or four factory feet is not always correct. With no other change, the right support yields punchier dynamics, smoother top end, less strain and grain in the midrange, higher-definition bass, improved soundstaging/dimensioning and a general reduction of digital hash. A portion of digititis normally blamed on jitter can be mitigated through maglev or bearings.