Can I delete iMessages from only my iPad?

The Golden Rule: Don’t share an AppleID between users. Each user should have their own AppleID for their own exclusive use - linked to their own primary email (and secondary/recovery email addresses and trusted telephone numbers). 

You would be best advised to separate your digital identities and configure a new AppleID for other users. If setting-up AppleID for a minor, you should set-up Family Sharing first - and create the AppleID for your grandchild from there.

Your grandchild should have their own AppleID - in fact, every user should have their own AppleID. This is essential to maintain intended separation of activities and to avoid unintended sharing of sensitive and data. Done properly, you’ll not have any issues with your content being visible to others, or content related to your child appearing on your own devices.

You may find this information to be helpful with setting-up an AppleID for a minor - and considering appropriate controls:

Apple for Kids - Official Apple Support

Help your child set up an iPhone, iPad, or iPod touch - Apple Support

Family Sharing and Apple ID for your child – Apple Support

Use parental controls on your child's iPhone, iPad and iPod touch – Apple Support

donnag3333 wrote:

Can I delete the iMessages app from an iPad? I’m setting one up for my grandson but do not want him to see my texts.

You should absolutely not share an Apple ID with your grandson. He should have his own. You can use Family Sharing to share content.

Set up Family Sharing - Apple Support

Sounds like you are planning to have the iPad connected to your Apple ID. That's not a good idea, for many more reasons than message privacy.

You should set up separate Apple ID for your grandson. You probably want to set him up in a Family Share group that you or his parent(s) manage.

You can also use restrictions mentioned in Screen Time and switch off messages and he won’t be able to open it https://support.apple.com/en-us/HT201304

You won’t be able to do that but you can sign out the Apple ID from it go to setting then scroll to messages tap on it and then choose sign out