Yes being able to practice speaking would be ideal for practicing production + building your confidence, have you tried something like HelloTalk? 
For general recall practice, I highly recommend doing something like KaniWani or KameSame alongside WaniKani. It’s one thing to do well with recognition (JP → EN), but recall (EN → JP) is an entirely different skill that requires consistent practice too – I know this all too well because when I first started KaniWani, my percentages were pretty awful despite doing well here on WK 
Maybe even trying to read your responses out loud as you’re doing KaniWani/KameSame reviews to get used to vocal recall could help, and then of course putting everything into practice through speaking whenever you can (talking to yourself can be okay practice too!)
Don’t let the apprehension of properly speaking hold you back from trying to talk to people when you go to Japan though, you may be pleasantly surprised at how far you can get with what you do currently know 