Yes. That's all you need.

1. Go to https://iancoleman.io/bip39/ (or download its source code and run locally for better security);
2. Write your recovery seed in the "BIP39 Mnemonic" field;
3. Scroll down a little bit and find your address in the list (the one you sent the USDT);
4. When you find it, copy its Private Key;
5. Now go to https://www.omniwallet.org/ and create an account;
6. Log in, go to My Wallet -> My Addresses;
7. Click on the "Add Address" button -> "Import Address with Private Key";
8. Paste your private key from step 4 -> "Add Address".
9. You should see your USDT balance and be able to send them somewhere else.