Hi CCAPPL,
I understand you want to share multiple photos from within the Photos app. If you are in the All Photos album, tap the Select button in the top-right corner, choose up to five photos, then tap the share button. If you choose more than five photos, Mail will not be an option. Here is some additional information from the iPhone User Guide for iOS 9.
Other ways to share photos and videos - iPhone
http://help.apple.com/iphone/9/#/iphf28f17237
You can share photos and videos in Mail or Messages, or through other apps you install.
Share or copy a photo or video. View a photo or video, then tap . If you don’t see , tap the screen to show the controls.
Tap More in Sharing to turn on the apps you want to use for sharing.
The size limit of attachments is determined by your service provider. iPhone may compress photo and video attachments, if necessary.
You can also copy a photo or video, then paste it into an email or text message (MMS or iMessage).
Share or copy multiple photos and videos. While viewing by moment, tap Share.
Save or share a photo or video you receive.
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Email: Tap to download it if necessary, then touch and hold the item to see sharing and other options.
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Text message: Tap the item in the conversation, then tap .
Photos and videos that you receive in messages or save from a webpage are saved to your Photos tab. They can also be viewed in the Camera Roll or, if you’re using iCloud Photo Library, the All Photos album.
Take care,