Yes. Google Play (and iTunes/App Store for iOS users) is a closed electronic marketplace handled by Google. Everything is handled via your Google account.
Since your CC sub is handled by Adobe (and separate from your Google account), there is really no easy way to get PS Touch included in your sub unless Adobe reimbursed you via a rebate. Paying for PS Touch does entitle you to any future updates and new features, though, plus you can keep it even if you ever decide to leave CC. (It's had several updates since it was first introduced.)